Merge pull request #63720 from dims/log-error-for-compute-v2-api

Automatic merge from submit-queue (batch tested with PRs 63367, 63718, 63446, 63723, 63720). 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>.

log error for os.NewComputeV2

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

Since we are returning false, we are kind of losing the error message,
so we should at least log it.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Related to https://github.com/kubernetes/cloud-provider-openstack/issues/169

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

pkg/cloudprovider/providers/openstack/openstack_instances.go

@@ -43,6 +43,7 @@ func (os *OpenStack) Instances() (cloudprovider.Instances, bool) {
 
 	compute, err := os.NewComputeV2()
 	if err != nil {
+		glog.Errorf("unable to access compute v2 API : %v", err)
 		return nil, false
 	}