Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/444411575e60
Author: Rudy Lu <me@rudy.lu>
Desc: Merge pull request #15410 from RudyLu/keyboard/Bug920431-keyboard_layout_customize

Bug 920431 - [keyboard] keyboard_layout.json should be customizable.
r=yurenju

========

https://hg.mozilla.org/integration/gaia-central/rev/7e172ca15416
Author: Rudy Lu <me@rudy.lu>
Desc: Bug 913782 - [Keyboard] Build time default keyboard selection work for
3rd-party keyboard support
 - make build/settings.js read the default keyboard layout config

Bug 920431 - [keyboard] keyboard_layout.json should be customizable
  - Refine to make it adopt the config in distribution package

========

https://hg.mozilla.org/integration/gaia-central/rev/0432fcd4b686
Author: Rudy Lu <me@rudy.lu>
Desc: Merge pull request #15704 from anefzaoui/missing-ar-char

Bug 926084 - [AR] Missing Arabic character in keyboard - Needs reorganization and using "alt" option.
r=rudylu

========

https://hg.mozilla.org/integration/gaia-central/rev/b299cf005a19
Author: Ahmed Nefzaoui <nefzaoui.ahmed@hotmail.com>
Desc: [AR] Missing Arabic character in keyboard - Needs reorganization and using alt option
Bumping manifests a=b2g-bump