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/mosquitto/Makefile

@@ -30,6 +30,7 @@ define Package/$(PKG_NAME)/default
   URL:=http://www.mosquitto.org/
   MAINTAINER:=Karl Palsson <karlp@remake.is>
   DEPENDS:= +librt
+  USERID:=mosquitto=200:mosquitto=200
 endef
 
 define Package/$(PKG_NAME)

net/mosquitto/files/mosquitto.init

@@ -14,7 +14,6 @@ SERVICE_DAEMONIZE=1
 SERVICE_WRITE_PID=1
 
 start() {
-        user_exists mosquitto 200 || user_add mosquitto 200
         if [ "$USE_UCI_CONFIG" -eq 1 ]; then
             CONF=/tmp/mosquitto.converted.$$.conf
             mosquitto.uci.convert -f $CONF