libubox: introduce generic logging api

Update to git head in order to introduce the new ulog() logging api which
supports early boot logging to dmesg.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

SVN-Revision: 44542

package/libs/libubox/Makefile

@@ -1,13 +1,13 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libubox
-PKG_VERSION:=2015-01-28
+PKG_VERSION:=2015-02-26
 PKG_RELEASE=$(PKG_SOURCE_VERSION)
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL:=http://git.openwrt.org/project/libubox.git
 PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
-PKG_SOURCE_VERSION:=827ad8337e88ec9e0bf73a8af1d6cf8555e8ef3d
+PKG_SOURCE_VERSION:=ca6d5472056ceee4b8ab320167e0ae8155a95985
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)-$(PKG_SOURCE_VERSION).tar.gz
 PKG_MIRROR_MD5SUM:=
 CMAKE_INSTALL:=1