Automatic merge from submit-queue (batch tested with PRs 47619, 47951, 46260, 48277)
iSCSi plugin: Remove redundant nil check
**What this PR does / why we need it**:
This patch is for cleanup of redundant nil check in iSCSI plugin.
This was mentioned at the code review on origin github thread.
https://github.com/openshift/origin/pull/14565
**Which issue this PR fixes**
**Special notes for your reviewer**:
**Release note**:
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NONE
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