build: Fix gettext domain after recent changes
build: Fix gettext domain after recent changes

Commit 1b11db36463116310ec2e40a7072d205a6536532 that switched the build
system to use upstream gettext intead glib-gettext accidentally changed
the gettext domain from atk10 to atk; this commit changes it back.

https://bugzilla.gnome.org/show_bug.cgi?id=763212

GNOME/at-spi2-core,Distrotech/atk,GNOME/at-spi2-core,GNOME/at-spi2-core,Distrotech/atk,Distrotech/atk