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

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https://hg.mozilla.org/integration/gaia-central/rev/2c2b93b70807
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #15871 from zacc/bug_965279

Bug 965729 - gaia-ui-tests - Tidy up persona app object

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https://hg.mozilla.org/integration/gaia-central/rev/004517d9ba7c
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 965729 - gaia-ui-tests - Tidy up persona app object
Bumping manifests a=b2g-bump