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

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https://hg.mozilla.org/integration/gaia-2_1/rev/d015a11512cb
Author: albertopq <apastor@mozilla.com>
Desc: Bug 1087042 - Rocketbar progressbar position in fullscreen-app

Conflicts:
	apps/system/test/marionette/lib/system.js

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https://hg.mozilla.org/integration/gaia-2_1/rev/042aaf7662ae
Author: Paco Rampas <pacorampas@gmail.com>
Desc: Bug 1086988 - [2.1][l10n][Usage] Multiple locales: If byte count reaches 3 digits it overlaps the source text next to it

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https://hg.mozilla.org/integration/gaia-2_1/rev/3394eef18f95
Author: Marcus Cavanaugh <m@mcav.com>
Desc: Bug 1084843 - For locales where first day of week is Monday, Repeat feature for alarms is broken.

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https://hg.mozilla.org/integration/gaia-2_1/rev/790210d5a059
Author: Tamara Hills <thills@mozilla.com>
Desc: Bug 1081854: GAIA follow-up to Bug 978639 (for GCF case 31.4.2.1.3). r=drs
Bumping manifests a=b2g-bump