Makefile: fix i18n build with ubus

Commit caf4d571e6d86285a3690cfcc8de9c5f394320a8 forgot adding
ubus_libs to build_libs for all-i18n target

Fixes:
 - http://autobuild.buildroot.org/results/c0b27754b7ede024c095bdf0b3616e6f6be48c6d

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
1 file changed