Fix containers with expired objects deletion problem

This fix adds a try/except statement around delete object function,
in order to be sure that even if one of the objects that is listed
in container is expired/is not found the containers will still
be deleted.

Change-Id: Ie49ce66304aefcb8264001b811859c8768e61fc7
Closes-Bug: #1281599
Merge "Fix containers with expired objects deletion problem"
Separate negative tests for test_instance_actions

Move negative tests from test_instance_actions.py to
test_instance_actions_negative.py

Partially implements blueprint negative-test-files

Change-Id: I283d445e8bef87caaf4af425f9745bbc3fed76ac
Merge "Separate negative tests for test_instance_actions"