Pause resource cleanup

When pause_teardown flag in tempest.conf is set to True a pdb breakpoint
is added to tearDown and tearDownClass methods in test.py.
This allows to pause cleaning resources process, so that, used resources
can be examined. Closer examination of used resources may lead to faster
debugging.

Change-Id: I09b7721e64cda161289f915d30888ec54bbed821
3 files changed