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

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https://hg.mozilla.org/integration/gaia-central/rev/7222259119d6
Author: Zibi Braniecki <zbigniew.braniecki@gmail.com>
Desc: Merge pull request #19166 from zbraniecki/992473-l10n-mutationobservers

Bug 992473 - Switch to use MutationObservers for DOM localization. r=stas, sr=vingtetun

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https://hg.mozilla.org/integration/gaia-central/rev/58582a2ec51e
Author: Zbigniew Braniecki <gandalf@mozilla.com>
Desc: Bug 992473 - Switch to use MutationObservers for DOM localization. r=stas, sr=vingtetun
Bumping manifests a=b2g-bump