Merge "Delete python bytecode before every test run"

tox.ini

@@ -9,11 +9,13 @@ usedevelop = True
 install_command = pip install -U {opts} {packages}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands = pip install pymongo===3.0.3
+commands = find . -type f -name "*.pyc" -delete
+           pip install pymongo===3.0.3
            {envpython} run_tests.py
            python setup.py testr --slowest
            {envpython} generate_examples.py
 whitelist_externals = bash
+                      find
 
 [tox:jenkins]
 sitepackages = True