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

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https://hg.mozilla.org/integration/gaia-central/rev/c8176900e040
Author: Yuren Ju <yurenju@gmail.com>
Desc: Merge pull request #21260 from yurenju/jshint-webapp-zip

Bug 1032050 - Fix jshint error for build/webapp-zip.js r=@cctuan

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https://hg.mozilla.org/integration/gaia-central/rev/440d56105b6d
Author: Yuren Ju <yurenju@gmail.com>
Desc: Bug 1032050 - Fix jshint error for build/webapp-zip.js
Bumping manifests a=b2g-bump