Add summary to Azure Alert.

This updates the Azure alert testing to add a summary which should be
sent to Azure as a commit-status genre.

Signed-off-by: Kevin McDermott <kevin@weave.works>

tests/azure/azure_test.go

@@ -842,6 +842,7 @@ func TestEventHubNotification(t *testing.T) {
 					Namespace: name,
 				},
 			},
+			Summary: "cluster: test-1",
 		}
 		return nil
 	})