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

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https://hg.mozilla.org/integration/gaia-central/rev/7e6a0f37716e
Author: Ed Morley <emorley@mozilla.com>
Desc: Revert "Bug 904068 - Implement build/settings.py in javascript" for breaking device image builds

This reverts commit f34e385890ead627ba7252ea30662b3a96172ea9.