Update nginx-slim image version and remove default command

docs/user-guide/petset.yaml

@@ -31,15 +31,10 @@ spec:
       terminationGracePeriodSeconds: 0
       containers:
       - name: nginx
-        image: gcr.io/google_containers/nginx-slim:0.7
+        image: gcr.io/google_containers/nginx-slim:0.8
         ports:
         - containerPort: 80
           name: web
-        command:
-        - nginx
-        args:
-        - -g
-        - "daemon off;"
         volumeMounts:
         - name: www
           mountPath: /usr/share/nginx/html

docs/user-guide/petset/bootstrapping/petset_peers.yaml

@@ -71,7 +71,7 @@ spec:
       terminationGracePeriodSeconds: 0
       containers:
       - name: nginx
-        image: gcr.io/google_containers/nginx-slim:0.7
+        image: gcr.io/google_containers/nginx-slim:0.8
         ports:
         - containerPort: 80
           name: web