Trim 50s from huawei ISCSIDriver unit tests

Trim 50s from huawei ISCSIDriver unit tests

The HuaweiISCSIDriver unit tests take almost a minute to run
on my machine because several negative test cases wait for
timeouts.

This commit leverages the utility method introduced in [1]
as well as the ZeroIntervalLoopingCall for mocks in the Huawei
unit tests to reduce total execution time for this set of
tests from about a minute to under 10s

[1] c2166876d85b17872c6fe32916c6d0d1dc974847

Change-Id: If17466ebabc391ebca57667200de072ede3ecc0c