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

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https://hg.mozilla.org/integration/gaia-2_1/rev/7b7c5c3bd339
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1054778 - [Rocketbar] Visual polish r=eli

Conflicts:
	apps/system/js/statusbar.js
	apps/system/style/chrome/chrome.css
	apps/system/style/statusbar/statusbar.css
Bumping manifests a=b2g-bump