Bumping gaia.json for 3 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/7d3e97220e38
Author: Zibi Braniecki <zbigniew.braniecki@gmail.com>
Desc: Merge pull request #20585 from zbraniecki/1022889-pretranslation-blacklist

Bug 1022889 - Introduce pretranslation blacklist. r=stas

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https://hg.mozilla.org/integration/gaia-central/rev/cc64708caf87
Author: Zbigniew Braniecki <gandalf@mozilla.com>
Desc: Bug 1022889 - Introduce pretranslation blacklist

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https://hg.mozilla.org/integration/gaia-central/rev/c38f8b1ff3e8
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1021496 - Follow-up, add grid_icon_renderer to example r=me
Bumping manifests a=b2g-bump