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

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https://hg.mozilla.org/integration/gaia-central/rev/a0371f6e89c2
Author: Gareth Aye <gaye@mozilla.com>
Desc: Merge pull request #15372 from millermedeiros/960170-chai-assert

Bug 960170 - [Calendar][Integration Test] use chai.assert instead of regular assert for better error messages r=gaye

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https://hg.mozilla.org/integration/gaia-central/rev/b77e3112ffcb
Author: millermedeiros <miller@millermedeiros.com>
Desc: Bug 960170 - [Calendar][Integration Test] use chai.assert instead of regular assert for better error messages