libubox: bump to version 2019-02-27

Contains the following change

	eeef7b5 blobmsg_json: blobmsg_format_string: do not escape '/'

Resolves FS#2147

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

package/libs/libubox/Makefile

@@ -1,13 +1,13 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libubox
-PKG_RELEASE=2
+PKG_RELEASE=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/libubox.git
-PKG_SOURCE_DATE:=2018-07-25
-PKG_SOURCE_VERSION:=c83a84afbef2b24f960ddeda0b5e2ab01fba6981
-PKG_MIRROR_HASH:=4a9594d2ae3706174d182a21fe815f1d18c20beca6593707cc757994975dc670
+PKG_SOURCE_DATE:=2019-02-27
+PKG_SOURCE_VERSION:=eeef7b50a06bc3c3218d560b4b513b4e7b19127f
+PKG_MIRROR_HASH:=0fa4c1299848717b983eb8b54110c6bd99447ed55f1d056192a181ced3ca32fc
 CMAKE_INSTALL:=1
 
 PKG_LICENSE:=ISC