Remove periods of docstring
Remove periods of docstring

Based on the desgin of openstack client, the docstring of each
function will be the help string for cli. Now all the other
services' commands don't use a period. So let's remove them
for zaqar to be consistent.

Change-Id: I9c8b18995c311d844a25c4a4da6be1aa6cc3790b

openstack/python-zaqarclient