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

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https://hg.mozilla.org/integration/gaia-central/rev/246baa233b51
Author: James Burke <jrburke@gmail.com>
Desc: Merge pull request #18970 from jrburke/bug940512-calendar-drawer-new

Bug 940512 - [calendar] change drawers to slide down UX r=gaye

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https://hg.mozilla.org/integration/gaia-central/rev/0df62dd52212
Author: jrburke <jrburke@gmail.com>
Desc: Bug 940512 - [calendar] change drawers to slide down UX for better integration with Haida app edge swiping
Bumping manifests a=b2g-bump