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

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https://hg.mozilla.org/integration/gaia-central/rev/dc0483a91071
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Revert "Bug 968661 - Extract new build module webapp-shared.js from webapp-zip.js"

This reverts commit 783dffa3dae6840df783198a795352093732569d.
Bumping manifests a=b2g-bump