Don't fall when just loading cinderv3 modules

this avoids loading warnings on salt-master that may not have
os-client-config installed, as salt tries to load them irrespective of
__virtual__() result.

Change-Id: I6b2e86d3bc64766ef86d8d0223a798467ef80e15
Related-Issue: https://mirantis.jira.com/browse/PROD-26920
1 file changed