include: add a meta data field for required system user:group

this is in preparation of having services run as !root with
ACL'ed access to ubus.

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

SVN-Revision: 42469

include/package-dumpinfo.mk

@@ -41,7 +41,8 @@ $(if $(VARIANT),Build-Variant: $(VARIANT)
 Category: $(CATEGORY)
 Title: $(TITLE)
 Maintainer: $(MAINTAINER)
-Source: $(PKG_SOURCE)
+$(if $(USERID),Require-User: $(USERID)
+)Source: $(PKG_SOURCE)
 Type: $(if $(Package/$(1)/targets),$(Package/$(1)/targets),$(if $(PKG_TARGETS),$(PKG_TARGETS),ipkg))
 $(if $(KCONFIG),Kernel-Config: $(KCONFIG)
 )$(if $(BUILDONLY),Build-Only: $(BUILDONLY)