Fix music-cassandra statefulset failing

imagePullSecrets was not present and thus preventing connecting to
registry where creds are mandatory

Change-Id: I766c0a1884cefa7fd643286dc899bf29d5946847
Issue-ID: OOM-1561
Signed-off-by: Sylvain Desbureaux <sylvain.desbureaux@orange.com>
diff --git a/kubernetes/common/music/charts/music-cassandra/templates/statefulset.yaml b/kubernetes/common/music/charts/music-cassandra/templates/statefulset.yaml
index 009c40d..da50744 100644
--- a/kubernetes/common/music/charts/music-cassandra/templates/statefulset.yaml
+++ b/kubernetes/common/music/charts/music-cassandra/templates/statefulset.yaml
@@ -136,3 +136,5 @@
           matchLabels:
             release: "{{ .Release.Name }}"
   {{- end }}
+      imagePullSecrets:
+      - name: "{{ include "common.namespace" . }}-docker-registry-key"