Delete all guests before launching tests
Delete all guests before launching tests

In case any guest was not deleted in last round of test, which
fails the test of current round, delete all guests before
launching the tests.

Change-Id: Ieb859824053f72425ccebd03e0ae38f9e52d2465

mfcloud/python-zvm-sdk,mfcloud/python-zvm-sdk,mfcloud/python-zvm-sdk,mfcloud/python-zvm-sdk