vmwareapi: remove unused fake vim logout method

Unused since I50acb4f1e85650f4c6dffe1a1d25842601be96bf removed the
__del__ implementation from the session.

Change-Id: Id3bc92d0c029eb86a43a67de7b9f2311d3a8e20c
Merge "vmwareapi: remove unused fake vim logout method"