Add missing unit tests for VMwareAPISession

This change adds unit tests for the following methods:
* pbm property
* _get_session_cookie
* invoke_api with stale session

It also updates one test for _create_session.

Change-Id: I4ab519a498f844e9c8b2889f84721935dfed1a5b
Add unittest method "test_download_flat_image"

Currently, there is not a test method of download_flat_image.

Change-Id: I8ed68222b3ef195464901d8c6442cc397ffdb272
Merge "Add missing unit tests for VMwareAPISession"
VMware: treat cases when SOAP reply does not have a body

There are cases when the SOAP reply does not return a body (for
example UnregisterVM may return this when running the CI).

This patch ensures that an exception is not thrown.

Change-Id: I394320641c648effd1209345cfd729e975f12aab
Closes-bug: #1300788
Fix vim25:InvalidRequest when no profiles exist

Currently, we don't check if there are any existing profiles in
pbm.get_all_profiles. As a result, we send a malformed request to
PBMRetrieveContent resulting in vim25:InvalidRequest.

Change-Id: I882c97a8050f8c2d49a4ce1de0f166e457ce68f2
Closes-Bug: #1302271
import run_cross_tests.sh from incubator

Change-Id: I1ba7f5e0879e71f456772d7b762c69bb0967fe18
Merge "Fix vim25:InvalidRequest when no profiles exist"