Remove __del__ usage in vmwareapi driver

The vmwareapi driver uses __del__ in an inappropriate way, which
causes spurious errors to be displayed at inconvenient times. The
python docs clearly detail the caveats of using __del__ (and even
provide a big red warning). This removes the offending code, which
can't work reliably anyway.

Closes-bug: 1262288
Change-Id: I50acb4f1e85650f4c6dffe1a1d25842601be96bf
Merge "Remove __del__ usage in vmwareapi driver"