Revert "Delete python bytecode before every test run"

I don't like recompiling my Python files on each run.

This reverts commit ce8957f04f.

Change-Id: I34cd22d249a201d3f5c948075dbd762085818cab

tox.ini

@@ -10,9 +10,7 @@ setenv = VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands =
-  find . -type f -name "*.pyc" -delete
   python setup.py testr --slowest --testr-args='{posargs}'
-whitelist_externals = find
 
 [tox:jenkins]
 downloadcache = ~/cache/pip