Fix missing ) in add_host

Fixes #1980.

lib/ansible/runner/action_plugins/add_host.py

@@ -37,7 +37,7 @@ class ActionModule(object):
     def run(self, conn, tmp, module_name, module_args, inject):
 
         if self.runner.check:
-            return ReturnData(conn=conn, comm_ok=True, result=dict(skipped=True, msg='check mode not supported for this module')
+            return ReturnData(conn=conn, comm_ok=True, result=dict(skipped=True, msg='check mode not supported for this module'))
 
         args = parse_kv(module_args)
         if not 'hostname' in args: