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

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https://hg.mozilla.org/integration/gaia-central/rev/ab449e5df779
Author: BavarianTomcat <tomcat@mozilla.com>
Desc: Revert "Bug 1053703 - Merge pre-app.js, app.js and post-app.js to one javascript file r=gduan" for build failures

This reverts commit 79e9bfc0994fada5e0cd0909a0bf7e553ccd7516.
Bumping manifests a=b2g-bump