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

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https://hg.mozilla.org/integration/gaia-central/rev/07a9b9b364c4
Author: Andrew Sutherland <asutherland@asutherland.org>
Desc: Merge pull request #18707 from Archaeopteryx/email-stringRemoval

Bug 1001817 - [email] remove unused localization strings from Firefox OS 2.0. r=jrburke, r=asuth

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https://hg.mozilla.org/integration/gaia-central/rev/56ebe71c017c
Author: Sebastian Hengst <archaeopteryx@coole-files.de>
Desc: Bug 1001817 - [email] remove unused localization strings from Firefox OS 2.0
Bumping manifests a=b2g-bump