after upgrade nebula-operator version, operator start failed

[jinyingsunny]

gcp environment, harris has created a nebula cluster on vesoft/nebula-operator:v1.4.2 ;
after upgrate operator version to reg.vesoft-inc.com/cloud-dev/nebula-operator:snap-1.4 ;

operator start failed

$ kubectl get pod -n nebula-operator-system
NAME                                                             READY   STATUS             RESTARTS        AGE
nebula-operator-controller-manager-deployment-7985874b6d-tsjgp   1/2     CrashLoopBackOff   8 (3m48s ago)   22m

logs:

$ kubectl logs nebula-operator-controller-manager-deployment-7985874b6d-tsjgp  -n nebula-operator-system
Defaulted container "controller-manager" out of: controller-manager, kube-rbac-proxy
I0731 06:52:43.774391       1 main.go:123] setup "msg"="Welcome to Nebula Operator."
I0731 06:52:43.774544       1 main.go:124] setup "msg"="Nebula Operator Version" "version"={"gitVersion":"6290403281110773-dev","gitCommit":"62904032811107735eb3147e7189b105a1374702","gitDate":"2023-05-31T08:16:46Z","buildDate":"2023-07-27T11:21:11Z","goVersion":"go1.19.7","compiler":"gc","platform":"linux/amd64"}
I0731 06:52:44.468606       1 listener.go:44] controller-runtime/metrics "msg"="Metrics server is starting to listen" "addr"=":8080"
I0731 06:52:45.779061       1 main.go:185] setup "msg"="starting manager"
I0731 06:52:45.779684       1 internal.go:369]  "msg"="Starting server" "addr"={"IP":"::","Port":8080,"Zone":""} "kind"="metrics" "path"="/metrics"
I0731 06:52:45.779729       1 internal.go:369]  "msg"="Starting server" "addr"={"IP":"::","Port":8081,"Zone":""} "kind"="health probe"
I0731 06:52:45.779792       1 leaderelection.go:248] attempting to acquire leader lease nebula-operator-system/nebula-controller-manager-leader...
I0731 06:53:02.839277       1 leaderelection.go:258] successfully acquired lease nebula-operator-system/nebula-controller-manager-leader
I0731 06:53:02.839674       1 controller.go:186]  "msg"="Starting EventSource" "controller"="nebulacluster" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaCluster" "source"="kind source: *v1alpha1.NebulaCluster"
I0731 06:53:02.839722       1 controller.go:186]  "msg"="Starting EventSource" "controller"="nebulacluster" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaCluster" "source"="kind source: *v1.ConfigMap"
I0731 06:53:02.839746       1 controller.go:186]  "msg"="Starting EventSource" "controller"="nebulacluster" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaCluster" "source"="kind source: *v1.Service"
I0731 06:53:02.839767       1 controller.go:186]  "msg"="Starting EventSource" "controller"="nebulacluster" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaCluster" "source"="kind source: *v1.StatefulSet"
I0731 06:53:02.839790       1 controller.go:186]  "msg"="Starting EventSource" "controller"="nebulacluster" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaCluster" "source"="kind source: *v1.Deployment"
I0731 06:53:02.839812       1 controller.go:194]  "msg"="Starting Controller" "controller"="nebulacluster" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaCluster"
I0731 06:53:02.839873       1 controller.go:186]  "msg"="Starting EventSource" "controller"="nebularestore" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaRestore" "source"="kind source: *v1alpha1.NebulaRestore"
I0731 06:53:02.839902       1 controller.go:194]  "msg"="Starting Controller" "controller"="nebularestore" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaRestore"
I0731 06:53:02.941119       1 controller.go:228]  "msg"="Starting workers" "controller"="nebularestore" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaRestore" "worker count"=5
I0731 06:53:02.941825       1 controller.go:228]  "msg"="Starting workers" "controller"="nebulacluster" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaCluster" "worker count"=3
I0731 06:53:02.942308       1 nebula_cluster_controller.go:160] Start to reconcile NebulaCluster
I0731 06:53:03.617499       1 nebula_cluster_controller.go:143] Finished reconciling NebulaCluster [harris/root], spendTime: (675.407398ms)
I0731 06:53:03.617838       1 controller.go:118]  "msg"="Observed a panic in reconciler: runtime error: invalid memory address or nil pointer dereference" "NebulaCluster"={"name":"root","namespace":"harris"} "controller"="nebulacluster" "controllerGroup"="apps.nebula-graph.io" "controllerKind"="NebulaCluster" "name"="root" "namespace"="harris" "reconcileID"="856655c4-0aaa-4158-82af-7dcaf6986454"
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x14a3141]

reason is nebula-cluster with logRotate open without set agent image and version。
but before upgrade ,it is ok.

Describe the bug (required)

upgrade normal

Your Environments (required)
nebula-ent-sc-rc包
镜像是：
image: reg.vesoft-inc.com/rc/nebula-storaged-ent
version: v3.5.0-sc
operator镜像是：
reg.vesoft-inc.com/cloud-dev/nebula-operator:snap-1.4

[MegaByte875]

#232

[jinyingsunny]

checked.