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

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https://hg.mozilla.org/integration/gaia-central/rev/a2ec8982eadf
Author: Amir Nissim <amirnissim@gmail.com>
Desc: Merge pull request #20573 from EverythingMe/1025889-first-load

1025889 first load

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https://hg.mozilla.org/integration/gaia-central/rev/271de3ff08ed
Author: Ran Ben Aharon <ran@ranbena.com>
Desc: Bug 1025889 - [Collection app] Load Pinned apps and Bg Image on open
Bumping manifests a=b2g-bump