Bumping gaia.json for 2 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/ad038535e85b
Author: Gregor Wagner <anygregor@gmail.com>
Desc: Merge pull request #14145 from nullaus/downloads-api

bug 938023 - Add downloads permission to test-container in gaia. r=fabri...

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https://hg.mozilla.org/integration/gaia-central/rev/aaed1c843b14
Author: Ghislain 'Aus' Lacroix <aus@mozilla.com>
Desc: bug 938023 - Add downloads permission to test-container in gaia. r=fabrice