drop mock dependency
drop mock dependency

mock is not used anywhere in the module, let's drop it.
This patch will help to hit this bug:
https://launchpad.net/bugs/1492636

Change-Id: Ic6e1dd9737fdd762eebb39628d08ece3e54bbe5d

openstack/puppet-monasca,openstack/puppet-monasca,openstack/puppet-monasca,openstack/puppet-monasca,openstack/puppet-monasca