clean up saio env. after runnning func tests

Added call to delete container in teardown_package().
Tests are leaving objects and containers in saio environment
after finishing running the tests.

Currently, delete_containers() is called in the setUp of each test
class, which cleans up the containers of the previous test,
but leaves the containers of the last test in the saio environment.

Change-Id: I643d7083a2a310fc3d24eab48c565f3798cff25f
Signed-off-by: Thiago da Silva <thiago@redhat.com>
Merge "clean up saio env. after runnning func tests"