VMware: add tests for spawn with config drive enabled

Add tests for test_vmops where config driver is enabled.

TrivialFix

Change-Id: I6ca9bfb32672d42987892ee4e95c0d33c3ef2685
VMware: fix compute node exception when no hosts in cluster

Commit 4033c0c9c16d2844b36fd5627717e7ce206887f6 casues the
regression. The result was a empty string and not None.
That is suds returns a Text object and not None.

Change-Id: I79e70e300f40eb3561cf56478d578f0f8cda273e
Closes-bug: #1383305
Merge "VMware: add tests for spawn with config drive enabled"
Merge "VMware: fix compute node exception when no hosts in cluster"