Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/fb52acdd0348
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Merge pull request #15980 from timdream/build-l10n-copy-bulid-stage

Bug 968187 - Localize manifests copied from build_stage, r=yuren

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https://hg.mozilla.org/integration/gaia-central/rev/c33ddaa3702c
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Bug 968187 - Localize manifests copied from build_stage
Bumping manifests a=b2g-bump