Refresh openstack-tools virtualenv every time

All of the commands there are idempotent. By not refreshing it, every
time we change this virtualenv initialization, such as the recent
addition of os-apply-config, we fail to build the virtualenv in the way
the rest of the code expects it to be built.

Change-Id: I07cefaf8348769cc7793936819175c1daaabd41b
Merge "Refresh openstack-tools virtualenv every time"