cmd/govulncheck: clean up test

staticcheck was complaining

Change-Id: I67c965b01f67ea907fdb5fa9b7a37447a49b9bde
Reviewed-on: https://go-review.googlesource.com/c/vuln/+/575135
Run-TryBot: Zvonimir Pavlinovic <[email protected]>
Reviewed-by: Ian Cottrell <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

cmd/govulncheck/test_utils.go

@@ -118,7 +118,7 @@ func loadConfig(path string) (*config, error) {
 	if err := json.Unmarshal(b, &cfg); err != nil {
 		return nil, err
 	}
-	for i, _ := range cfg.Fixups {
+	for i := range cfg.Fixups {
 		cfg.Fixups[i].init()
 	}
 	return &cfg, nil