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

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https://hg.mozilla.org/integration/gaia-1_4/rev/a48cb118290e
Author: Justin D'Arcangelo <justindarc@gmail.com>
Desc: Merge pull request #18262 from justindarc/bug995632

Bug 995632 - [camera] zoom gesture sensitivity is depends on screen reso...
Bumping manifests a=b2g-bump