ubus: prepare to run ubusd as non-root user

Move /var/run/ubus.sock to /var/run/ubus/ubus.sock in preparation for
having ubusd run as non-root user.

Signed-off-by: Daniel Golle <[email protected]>

package/system/ubus/Makefile

@@ -5,9 +5,9 @@ PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/ubus.git
-PKG_SOURCE_DATE:=2020-02-05
-PKG_SOURCE_VERSION:=171469e3138cce191892e20b6fd35b52c9368064
-PKG_MIRROR_HASH:=b4f1a3d70c2685c2aee2724b980b2ff747f8662f74d04d8be1c5a5e950b0e2ef
+PKG_SOURCE_DATE:=2020-10-21
+PKG_SOURCE_VERSION:=13a4438b4ebdf85d301999e0a615640ac4c9b0a8
+PKG_MIRROR_HASH:=e9e88bb78993a31a33a1c9579f1facca2949c1a4397b842a9f1b469b170be5da
 CMAKE_INSTALL:=1
 
 PKG_LICENSE:=LGPL-2.1
@@ -31,6 +31,7 @@ define Package/ubusd
   CATEGORY:=Base system
   TITLE:=OpenWrt RPC daemon
   DEPENDS:=+libubox +libblobmsg-json
+  USERID:=ubus=81:ubus=81
 endef
 
 define Package/libubus