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

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https://hg.mozilla.org/integration/gaia-central/rev/889e702453a0
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Merge pull request #15470 from wilsonpage/bug/961029

Bug 961029 - [Camera] Fix remaining broken ('skipped') unit tests

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https://hg.mozilla.org/integration/gaia-central/rev/52559b221f20
Author: Wilson Page <wilsonpage@me.com>
Desc: Bug 961029 - [Camera] Fix remaining broken ('skipped') unit tests
Bumping manifests a=b2g-bump