Fix openSUSE dashboard file locations

The openstack packaging has been changed so that the horizon packages
are now in /srv. Update all occurences.

Not backported: doc/admin-guide-cloud/ch_compute.xml

Change-Id: Ib53c7ba7396e7f99433068d7a4625b12bd918957
Closes-Bug: #1279892
backport: havana
(cherry picked from commit cdbf99aa92e4d60e410768ef86016f431b56186c)