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

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https://hg.mozilla.org/integration/gaia-central/rev/1d2b5c832da6
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #19910 from svic/Bug_998175_rebased

Bug 998175 - Properly handle concurrent file transfers

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https://hg.mozilla.org/integration/gaia-central/rev/0dd3b4089242
Author: Arno Puder <arno@puder.org>
Desc: Bug 998175 - Properly handle concurrent file transfers

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https://hg.mozilla.org/integration/gaia-central/rev/7c09a03e0ff2
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #21512 from anefzaoui/bug-876825

Bug 876825 - Mixed LTR & RTL content support in text input fields and textarea

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https://hg.mozilla.org/integration/gaia-central/rev/27d2b92ab927
Author: Ahmed Nefzaoui <nefzaoui.ahmed@hotmail.com>
Desc: Bug 876825 - Mixed LTR & RTL content support in text input fields and textarea
Bumping manifests a=b2g-bump