GlusterFS: Use default namespace when not native.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1476197

Signed-off-by: Jose A. Rivera <jarrpa@redhat.com>

roles/openshift_storage_glusterfs/defaults/main.yml

@@ -1,6 +1,6 @@
 ---
 openshift_storage_glusterfs_timeout: 300
-openshift_storage_glusterfs_namespace: 'glusterfs'
+openshift_storage_glusterfs_namespace: "{{ 'glusterfs' | quote if glusterfs_is_native or glusterfs_heketi_is_native else 'default' | quote }}"
 openshift_storage_glusterfs_is_native: True
 openshift_storage_glusterfs_name: 'storage'
 openshift_storage_glusterfs_nodeselector: "glusterfs={{ openshift_storage_glusterfs_name }}-host"