Remove any existing coverage files

tox.ini

@@ -10,6 +10,8 @@ envlist = {py27,py36,pypy}-{aws,azure,gcp,openstack,mock}
 
 [testenv]
 commands = flake8 cloudbridge tests setup.py
+           # delete existing coverage files
+           rm /home/travis/build/CloudVE/cloudbridge/.coverage*
            # see setup.cfg for options sent to nosetests and coverage
            nosetests -v --nocapture --nologcapture --logging-format='%(asctime)s [%(levelname)s] %(name)s: %(message)s' {posargs}
 setenv =