generic userid: use the new USERID api

recent changes in trunk allow us to specify the userid inside the openwrt makefile.
the info is stored int he meta data of the IPK contorl file and users are generated
by the new generic postinst trigger.

Signed-off-by: John Crispin <blogic@openwrt.org>

net/portmap/Makefile

@@ -29,6 +29,7 @@ define Package/portmap
   TITLE:=The RPC Portmapper
   URL:=http://neil.brown.name/portmap/
   MAINTAINER:=Peter Wagner <tripolar@gmx.at>
+  USERID:=rpc=65533:rpc=65533
 endef
 
 define Package/portmap/description

net/portmap/files/portmap.init

@@ -7,9 +7,6 @@ STOP=19
 USE_PROCD=1
 
 start_service() {
-	user_exists rpc 65533 || user_add rpc 65533 65533 rpc /var/empty
-	group_exists rpc 65533 || group_add rpc 65533
-	
 	procd_open_instance
 	procd_set_param command /usr/sbin/portmap -f
 	procd_close_instance