Bumping gaia.json for 2 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/470561ec47ab
Author: James Lal <james@lightsofapollo.com>
Desc: Merge pull request #11737 from lightsofapollo/rework-calendar-test

Bug 908983 - Remove use of querySelector

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https://hg.mozilla.org/integration/gaia-central/rev/78b0660aa519
Author: James Lal <james@lightsofapollo.com>
Desc: Bug 908983 - Remove use of querySelector