moved gluster to 3.8

Change-Id: I0d61fa2e6561b09538bf73969fc8629247cb62e3
diff --git a/init.yml b/init.yml
index 789e1af..75554ff 100644
--- a/init.yml
+++ b/init.yml
@@ -242,7 +242,7 @@
             distributions:
             - ubuntu-xenial/stable
         mirantis_openstack_xenial_glusterfs:
-          components: '3.12'
+          components: '3.8'
           publisher:
             distributions:
             - ubuntu-xenial/glusterfs/stable