Using openonu-go 1.2.8 in openonu chart 2.7.15

Change-Id: Iba86babbc7394eb1abca98b32c31ac1f7d050f86
diff --git a/voltha-stack/Chart.yaml b/voltha-stack/Chart.yaml
index f8f8623..74398ba 100644
--- a/voltha-stack/Chart.yaml
+++ b/voltha-stack/Chart.yaml
@@ -28,7 +28,7 @@
 name: voltha-stack
 
 appVersion: "1.0"
-version: 0.1.16
+version: 0.1.17
 
 dependencies:
   - name: voltha
@@ -37,7 +37,7 @@
     condition: voltha.enabled
   - name: voltha-adapter-openonu
     repository: file://../voltha-adapter-openonu
-    version: 2.7.14
+    version: 2.7.15
     condition: voltha-adapter-openonu.enabled
   - name: voltha-adapter-openolt
     repository: file://../voltha-adapter-openolt