Mount netns as shared.

Since mount propagation is not supported in kubernetes API yet, we need
to set it as shared.

Also adds hostIPC for stackube-proxy.

Change-Id: Ie31761a12f169d9afde52e56b7068adaa8f2a127
Closes-Bug: 1710830
Signed-off-by: Pengfei Ni <feiskyer@gmail.com>

deployment/stackube-proxy.yaml

@@ -46,6 +46,7 @@ spec:
     spec:
       hostNetwork: true
       hostPID: true
+      hostIPC: true
       serviceAccountName: stackube-proxy
       dnsPolicy: ClusterFirst
       restartPolicy: Always
@@ -108,7 +109,9 @@ spec:
                   name: stackube-config
                   key: kubernetes-port
           volumeMounts:
-            - mountPath: /var/run/netns
+            # mount as shared because mount propagation is not supported
+            # in kubernetes api yet.
+            - mountPath: /var/run/netns:shared
               name: netns
             - mountPath: /etc/ssl/certs
               name: certs