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: Ib095a107537446d6e43a222cf68f7b84b9368f60
Closes-Bug: #1368661

tox.ini

@@ -9,9 +9,11 @@ setenv = VIRTUAL_ENV={envdir}
 usedevelop = True
 install_command = pip install -U {opts} {packages}
 deps = -r{toxinidir}/test-requirements.txt
-commands = python monasca_test_setup.py
+commands = find . -type f -name "*.pyc" -delete
+           python monasca_test_setup.py
            python setup.py testr --slowest --testr-args="{posargs}"
 whitelist_externals = bash
+                      find
 
 [testenv:pep8]
 deps = -r{toxinidir}/pep8-test-requirements.txt