Split test repository for galera to match upstream

Galera repository has changed in upstream and has
divided wsrep and galera directories.
This patch sets up 2 repositories `galera-3` and
`mysql`wsrep-5.6`.

Signed-off-by: Ondrej Vasko <ondrej.vaskoo@gmail.com>

tests/pillar/repo_galeracluster.sls

     enabled: true
     repo:
       galeracluster:
-        source: 'deb http://releases.galeracluster.com/ubuntu {{ grains.get('oscodename') }} main'
+        source: 'deb http://releases.galeracluster.com/galera-3/ubuntu {{ grains.get('oscodename') }} main'
+        key_id: BC19DDBA
+        key_server: hkp://p80.pool.sks-keyservers.net:80
+      mysql-wsrep:
+        source: 'deb http://releases.galeracluster.com/mysql-wsrep-5.6/ubuntu {{ grains.get('oscodename') }} main'
         key_id: BC19DDBA
         key_server: hkp://p80.pool.sks-keyservers.net:80
       mitaka-staging_PPA: