Automatic merge from submit-queue (batch tested with PRs 54229, 54380, 54302, 54454). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

RBD Plugin: rbdStatus only check output of successful `rbd status` run

**What this PR does / why we need it**:

Current RBDUtil.rbdStatus implementation never return error in any cases, even if command not found or `rbd status` never succeed. This PR change it to only check output of successful `rbd status` run, and return error on other cases.

Because there are maybe network problem or ceph cluster unresponsive conditions which will cause `rbd status` command to fail. We cannot assume there is no watchers on given image. It's better to return error, and let the caller to decide what to do.

**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
```