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

Bring over the cleaning line from run_tests.sh for the pyc files to
all the tox runs.

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

Change-Id: I5eb5d3a017ef752178073d7389961fd0ff4be4c4
Closes-Bug: #1368661

stackforge/monasca-statsd,stackforge/monasca-statsd