Document the return value of the update method (as requested on -dev list)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@177096 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/config.h

@@ -152,7 +152,7 @@ struct ast_config *ast_load_realtime_multientry(const char *family, ...);
  * \param keyfield which field to use as the key
  * \param lookup which value to look for in the key field to match the entry.
  * This function is used to update a parameter in realtime configuration space.
- *
+ * \return Number of rows affected, or -1 on error.
  */
 int ast_update_realtime(const char *family, const char *keyfield, const char *lookup, ...);