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

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https://hg.mozilla.org/integration/gaia-central/rev/a38570b9bb58
Author: Albert <acperez@tid.es>
Desc: Merge pull request #15812 from acperez/bug-965327

Bug 965327: Running install-gaia.js on node.js fails copying single variant. r=yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/9ba55e6c7556
Author: Albert <acperez@tid.es>
Desc: Bug 965327: Running install-gaia.js on node.js fails copying single variant. r=yurenju
Bumping manifests a=b2g-bump