Increase backoffLimit to 10 for helm installer

The helm installer often quickly reaches the backoffLimit of 5. Increase
this to 10 so that there is a greater chance of successful installation.

Story: 2006765
Task: 37783

Change-Id: I5293c970bb1696f14c421fdf67abb495b4b8d666
Signed-off-by: Bharat Kunwar <brtknr@bath.edu>

magnum/drivers/common/templates/kubernetes/helm/ingress-nginx.sh

@@ -213,7 +213,7 @@ metadata:
   name: install-${CHART_NAME}-job
   namespace: magnum-tiller
 spec:
-  backoffLimit: 5
+  backoffLimit: 10
   template:
     spec:
       serviceAccountName: tiller

magnum/drivers/common/templates/kubernetes/helm/metrics-server.sh

@@ -48,7 +48,7 @@ metadata:
   name: install-${CHART_NAME}-job
   namespace: magnum-tiller
 spec:
-  backoffLimit: 5
+  backoffLimit: 10
   template:
     spec:
       serviceAccountName: tiller

magnum/drivers/common/templates/kubernetes/helm/prometheus-adapter.sh

@@ -83,7 +83,7 @@ metadata:
   name: install-${CHART_NAME}-job
   namespace: magnum-tiller
 spec:
-  backoffLimit: 5
+  backoffLimit: 10
   template:
     spec:
       serviceAccountName: tiller

magnum/drivers/common/templates/kubernetes/helm/prometheus-operator.sh

@@ -166,7 +166,7 @@ metadata:
   name: install-${CHART_NAME}-job
   namespace: magnum-tiller
 spec:
-  backoffLimit: 5
+  backoffLimit: 10
   template:
     spec:
       serviceAccountName: tiller