Merge the tip of origin/release/proposed/2019.2.0 into origin/release/2019.2.0

1f165df Fix typo for Ceph errorMsg call
32b62ea Fix check for empty list
365eb25 Drop not needed ceph connectOS function from installClients stage
83bf4c2 Fixup typo in call for ceph.installClient()
0e12ee6 move function to ceph class

Change-Id: If27afab562cfc4de8c9ec5a478cddefeec42e11c