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

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https://hg.mozilla.org/integration/gaia-central/rev/b693850589c0
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #18502 from zbraniecki/999163-cleanup-mozl10n-api-ftu

Bug 999163 - Clean up bootstrap mozL10n API use in FTU

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https://hg.mozilla.org/integration/gaia-central/rev/8b525da78d8e
Author: Zbigniew Braniecki <gandalf@mozilla.com>
Desc: Bug 999163 - Clean up bootstrap mozL10n API use in FTU
Bumping manifests a=b2g-bump