add missing error check in decomposedfs

[butonic]

During space creation the decomposedfs now checks for errors when trying to read the root node. This prevents a panic by no longer calling InternalPath on the node.

Seen in the stacktrace of owncloud/ocis#4961

[micbar]

@butonic can you add this to get a green ci

diff --git a/.drone.star b/.drone.star
index a8f978798..f0d73896d 100644
--- a/.drone.star
+++ b/.drone.star
@@ -313,16 +313,6 @@ def coverage():
                     "make test",
                 ],
             },
-            {
-                "name": "codacy",
-                "image": "plugins/codacy:1",
-                "pull": "always",
-                "settings": {
-                    "token": {
-                        "from_secret": "codacy_token",
-                    },
-                },
-            },
         ],
         "depends_on": ["changelog"],
     }