Bumping gaia.json for 1 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/2c7112a9eb3a
Author: Dave Hunt <dave.hunt@gmail.com>
Desc: Revert "Bug 915672 - Modify marionette test driver scripts to add support for gathering power draw data. r=dhunt r=jgriffin"

This reverts commit e44921850131b3671592e669f73f500dee4caf7d.