uci: update to HEAD of lede-17.01 branch

Switch uci to the lede-17.01 branch which contains the following two commits
cherry-picked from uci master:

141b64e lua: additionally return name when looking up sections
1e17f24 lua: support extended section notation

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

package/system/uci/Makefile

@@ -13,9 +13,9 @@ PKG_RELEASE:=1
 
 PKG_SOURCE_URL=$(LEDE_GIT)/project/uci.git
 PKG_SOURCE_PROTO:=git
-PKG_SOURCE_DATE=2016-07-04
-PKG_SOURCE_VERSION:=e1bf4356e1b513e158e1b5049147087ed6342cfd
-PKG_MIRROR_HASH:=4994a10a9e15f71312502f8babf045da7cea18c64227b387fc2dcf64f2252f19
+PKG_SOURCE_DATE=2018-01-01
+PKG_SOURCE_VERSION:=141b64ef84f43c954e665865b1bbf216fbf7c05f
+PKG_MIRROR_HASH:=fbd837a16cfa6b0d80f5a4b332b86a105a2b9d37480bcc777931fdea7ce601c9
 
 PKG_LICENSE:=LGPL-2.1
 PKG_LICENSE_FILES:=