httping: fix build without host-gettext

httping: fix build without host-gettext

Since commit 654de6512554c (httping: use the new gettext logic), host-gettext
is not a dependency of httping. This breaks the build because the httping
Makefile calls msgfmt unconditionally. Add a patch that allows build without
translation files generation.

Fixes:
http://autobuild.buildroot.net/results/73e/73e624775617d1b95da7d4ef666612af5bceef61/
http://autobuild.buildroot.net/results/2bf/2bff43d7b749b4daf32868bddbae94b510949bf8/
http://autobuild.buildroot.net/results/8a6/8a69659afa21f467ca5de7915363cebf0fc7aff2/

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Gilles Talis <gilles.talis@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>