libubox: update to the latest version

- Improves C++ compatibility
- Adds static initializers for the kvlist API

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

package/libs/libubox/Makefile

 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libubox
-PKG_VERSION:=2016-07-29
+PKG_VERSION:=2016-11-29
 PKG_RELEASE=$(PKG_SOURCE_VERSION)
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(LEDE_GIT)/project/libubox.git
 PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
-PKG_SOURCE_VERSION:=290c64ef5b5c3e75be851594f269d6a9568e64e5
+PKG_SOURCE_VERSION:=77a629375d7387a33a59509d9d751a8798134cab
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)-$(PKG_SOURCE_VERSION).tar.xz
-PKG_MIRROR_MD5SUM:=aa96245c94a44e171fb58b517003b6d6958cd764216df84f4c5bcf570eca0974
+PKG_MIRROR_MD5SUM:=686a0078da3ada68fc9d39f62df07be52589afce79969ec4039f38f85ccedd3c
 CMAKE_INSTALL:=1
 
 PKG_LICENSE:=ISC