Delete python bytecode before every test run.
Delete python bytecode before every test run.

This should eliminate the need to clean -x -i to kill pyc files in
your local directory to get tests to pass.

Change-Id: Ia6f81dfd1c6487c293012623a165d9dd474b0f4f
Closes-Bug: #1368661

StackStorm/mistral,openstack/mistral,openstack/mistral,StackStorm/mistral