Use correct service name in cainstance.backup_config

https://fedorahosted.org/freeipa/ticket/4754

Reviewed-By: Martin Kosek <mkosek@redhat.com>

ipaserver/install/cainstance.py

@@ -1699,7 +1699,8 @@ def backup_config(dogtag_constants=None):
     if dogtag_constants is None:
         dogtag_constants = dogtag.configured_constants()
 
-    if services.knownservices.dogtag.is_running():
+    if services.knownservices[dogtag_constants.SERVICE_NAME].is_running(
+        dogtag_constants.PKI_INSTANCE_NAME):
         raise RuntimeError("Dogtag must be stopped when creating backup of %s"
                            % dogtag_constants.CS_CFG_PATH)
     shutil.copy(dogtag_constants.CS_CFG_PATH,