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

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https://hg.mozilla.org/integration/gaia-central/rev/ff53bb09ef62
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Merge pull request #16115 from pivanov/bug-969484

Bug 969484

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https://hg.mozilla.org/integration/gaia-central/rev/046d35ad9a65
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 969484 - [VDR][Settings] Apply Buttons and Input areas [BB]
Bumping manifests a=b2g-bump