Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/7404866e6b75
Author: Jan Jongboom <janjongboom@gmail.com>
Desc: Merge pull request #17702 from comoyo/colemak

Bug 976248 - Colemak keyboard layout added. r=janjongboom

========

https://hg.mozilla.org/integration/gaia-central/rev/7ea01dd8f59f
Author: Liszy Szilveszter <cryorat@fedoraproject.org>
Desc: Bug 976248 - Colemak keyboard layout added
Bumping manifests a=b2g-bump