QA: test renewing the cluster certificate only

Currently, there is not test for just running renew-crypto
to only renew the cluster certificate (and not the node
certificates). This patches adds the test.
Signed-off-by: Helga Velroyen <helgav@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

qa/qa_cluster.py

@@ -1245,6 +1245,12 @@ def TestClusterRenewCrypto():
     _AssertSsconfCertFiles(master)
     AssertCommand(["gnt-cluster", "verify"])
 
+    # Only renew cluster certificate
+    AssertCommand(["gnt-cluster", "renew-crypto", "--force",
+                   "--new-cluster-certificate"])
+    _AssertSsconfCertFiles(master)
+    AssertCommand(["gnt-cluster", "verify"])
+
     # Restore RAPI certificate
     AssertCommand(["gnt-cluster", "renew-crypto", "--force",
                    "--rapi-certificate=%s" % rapi_cert_backup])