Add 'rm -f .testrepository/times.dbm' command in testenv
Add 'rm -f .testrepository/times.dbm' command in testenv

Running py2* post py3* tests results in error. Add
'rm -f .testrepository/times.dbm' command in testenv to
resolve this.

Change-Id: Ia6e132573b4d60f6720e1f134bda124c88fc8241

openstack/python-vitrageclient