add optional prefix arg to set_user FSCORE-429

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@14789 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/applications/mod_dptools/mod_dptools.c

@@ -404,7 +404,7 @@ SWITCH_STANDARD_APP(three_way_function)
 	}
 }
 
-#define SET_USER_SYNTAX "<user>@<domain>"
+#define SET_USER_SYNTAX "<user>@<domain> [prefix]"
 SWITCH_STANDARD_APP(set_user_function)
 {
 	switch_ivr_set_user(session, data);