The version we were using has been deprecated and is no longer
available, making the withVersion test no longer pass. I've bumped it to
the latest available version.
Google Container Engine's cluster API returned instance group manager
URLs when it meant to return instance group URLs. See #4336 for details
about the bug.
While this is undeniably an upstream problem, this PR:
* detects the error, meaning it will work as expected when the API is
fixed.
* corrects the error by requesting the instance group manager, then
retrieving its instance group URL, and using that instead.
* adds a test that exercises the error and the solution, to ensure it is
functioning properly.
Some google resources required network be refernced by resource URL (aka self_link), while others required network name.
This change allows either to be supplied.
DRY it out, and add a fix for #5552.
