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

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https://hg.mozilla.org/integration/gaia-central/rev/278dd1b102a3
Author: punamdahiya <punamdahiya@yahoo.com>
Desc: Merge pull request #21211 from andrewzhi/bug1020766

Bug 1020766 - [Flatfish][Gallery]Gallery app shows last-deleted photo in  the preview window

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https://hg.mozilla.org/integration/gaia-central/rev/37c47867f72b
Author: Andrew Zhi <ader.cch@gmx.com>
Desc: Bug 1020766 - Fix [Flatfish][Gallery]Gallery app shows last deleted-photo in the preview window
Bumping manifests a=b2g-bump