Automatic merge from submit-queue (batch tested with PRs 49651, 49707, 49662, 47019, 49747)
remove the redundant err define
**What this PR does / why we need it**:
some place has define err ,like
class, err := volutil.GetClassForVolume(d.plugin.host.GetKubeClient(), d.spec)
so delete the err define!
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```