Pin to working voltha/voltha-onos image

Change-Id: Ied1b7ab1fd53d759c1d5d3c1b4a088149559ce26
diff --git a/kubernetes-configs/voltha/tucson-pod.yml b/kubernetes-configs/voltha/tucson-pod.yml
index 6cbbf50..0acb97a 100644
--- a/kubernetes-configs/voltha/tucson-pod.yml
+++ b/kubernetes-configs/voltha/tucson-pod.yml
@@ -11,3 +11,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+images:
+  onos:
+    repository: voltha/voltha-onos@sha256
+    tag: 9f781ace4c6f4bf3b2e5ff9cb9f26aa4b328284da1d6b6523636dca1375d7666