Make Manila UI be installed after Horizon
Make Manila UI be installed after Horizon

Recent devstack change [1] made Horizon be installed at later point than it
was. It is inconsistent with our Devstack plugin that now installs Manila UI
earlier than Horizon. So, postpone installation of Manila UI until Horizon
exists and fix gates by this action.

[1] I8bf2ceaf7734c4f7cec68bc05d7cdbae81ef311e

Change-Id: Icb2fc77235cb7f6ec4349dacddf262c3e3be76c2
Closes-Bug: #1532300

vponomaryov/manila,bswartz/manila,scality/manila,NetApp/manila,bswartz/manila,NetApp/manila,openstack/manila,scality/manila,vponomaryov/manila,openstack/manila