Bumping gaia.json for 3 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/61db56e065e5
Author: Rudy Lu <me@rudy.lu>
Desc: Merge pull request #13971 from RudyLu/keyboard/bulgarian_keyboard_layouts

Bug 936840 - Added Bulgarian keyboard layouts.
r=rudylu

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https://hg.mozilla.org/integration/gaia-central/rev/aa93c5fa634c
Author: Mihail Chilyashev <chilyashev@gmail.com>
Desc: Bug 936840 - Added Bulgarian keyboard layouts

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https://hg.mozilla.org/integration/gaia-central/rev/b8bbc544eca9
Author: Dave Hunt <dave.hunt@gmail.com>
Desc: Bug 943817 - Marionette timeouts are lost when using the --restart command line option. r=zcampbell