Fix module name in API docs (#44)

Signed-off-by: Webster Mudge <wmudge@cloudera.com>

Author: wmudge

plugins/modules/df_service.py

@@ -24,7 +24,7 @@
 
 DOCUMENTATION = r'''
 ---
-module: df
+module: df_service
 short_description: Enable or Disable CDP DataFlow Services
 description:
     - Enable or Disable CDP DataFlow Services