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

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https://hg.mozilla.org/integration/gaia-central/rev/38469787521c
Author: Zibi Braniecki <zbigniew.braniecki@gmail.com>
Desc: Merge pull request #21124 from zbraniecki/994519-add-setattributes

Bug 994519 - Introduce l10n.setAttributes and l10n.getAttributes. r=stas

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https://hg.mozilla.org/integration/gaia-central/rev/ae5a34f50aa9
Author: Zbigniew Braniecki <gandalf@mozilla.com>
Desc: Bug 994519 - Introduce l10n.setAttributes and l10n.getAttributes. r=stas
Bumping manifests a=b2g-bump