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

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https://hg.mozilla.org/integration/gaia-central/rev/dc5880a24760
Author: James Lal <james@lightsofapollo.com>
Desc: Merge pull request #14533 from zacc/bug_925266

Bug 925266 - Setup gaia-ui-tests HTML report creation for Travis artifac...

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https://hg.mozilla.org/integration/gaia-central/rev/d9b87e6828fa
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 925266 - Setup gaia-ui-tests HTML report creation for Travis artifacts r=lightsofapollo