ubus: update to the latest version, adds object remove fixes

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/system/ubus/Makefile

@@ -1,13 +1,13 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=ubus
-PKG_VERSION:=2016-07-02
+PKG_VERSION:=2016-08-23
 PKG_RELEASE=$(PKG_SOURCE_VERSION)
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(LEDE_GIT)/project/ubus.git
 PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
-PKG_SOURCE_VERSION:=053be7df871e05478284235732f8b0608089512f
+PKG_SOURCE_VERSION:=686c05d738a7a1f7ec62c47807f07f6f642904b1
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)-$(PKG_SOURCE_VERSION).tar.gz
 PKG_MIRROR_MD5SUM:=
 CMAKE_INSTALL:=1