Fix bugs and pin osm bundles

Keystone charm (bug 1378): Improve the way we handle the relation data from the database
relation
Ro charm (bug 1379): Fix the status of the non-leader units
Ng-ui (bug 1380): Fix the nbi-relation-changed hook for the non-leader
units
Installer: Pin the version of the OSM bundles

Change-Id: Ied07c964b1c85b1c534916eb4b30fd6bc87287a6
Signed-off-by: David Garcia <david.garcia@canonical.com>