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

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https://hg.mozilla.org/integration/gaia-central/rev/508eaa6999cf
Author: James Burke <jrburke@gmail.com>
Desc: Merge pull request #22899 from jrburke/bug1050725-email-notranslate-overpaint

Bug 1050725 - Reduce overpaint of the email app. Patch from vingtetun, r=jrburke

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https://hg.mozilla.org/integration/gaia-central/rev/2036f5bc7793
Author: jrburke <jrburke@gmail.com>
Desc: Bug 1050725 - Reduce overpaint of the email app
Bumping manifests a=b2g-bump