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

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https://hg.mozilla.org/integration/gaia-central/rev/da2ca9acb133
Author: Miller Medeiros <miller@millermedeiros.com>
Desc: Merge pull request #20036 from millermedeiros/974731-create-event-test

Bug 974731 - Failing calendar marionette test create_event_test.js r=gaye

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https://hg.mozilla.org/integration/gaia-central/rev/bff25a63af76
Author: Miller Medeiros <miller@millermedeiros.com>
Desc: Bug 974731 - Failing calendar marionette test create_event_test.js
Bumping manifests a=b2g-bump