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

========

https://hg.mozilla.org/integration/gaia-central/rev/89b8da43560a
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Merge pull request #14026 from pivanov/bug-942973

Bug 942973 - [System][Notifications] 1.3 Visual Refresh of Notification Icons

========

https://hg.mozilla.org/integration/gaia-central/rev/871a880433ca
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 942973 - [System][Notifications] 1.3 Visual Refresh of Notification Icons

========

https://hg.mozilla.org/integration/gaia-central/rev/f398259f64e2
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Merge pull request #13986 from pivanov/bug-919530

Bug 919530 - [Clock] Dark UI for Settings a new or editing an alarm

========

https://hg.mozilla.org/integration/gaia-central/rev/a055dc0a4c65
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 919530 - [Clock] Dark UI for Settings a new or editing an alarm