Fix the bug of "Fix spelling typo in trove"
Fix the bug of "Fix spelling typo in trove"

The word "persistant" should be spelled as "persistent",
so it is changed.

Change-Id: Ifc3e55b379ed338088e0fe73096e4573a8b2bee9
Closes-Bug: #1499638

mmasaki/trove,openstack/trove,redhat-openstack/trove,zhangg/trove,hplustree/trove,redhat-openstack/trove,mmasaki/trove,zhangg/trove,hplustree/trove,redhat-openstack/trove,mmasaki/trove,openstack/trove