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

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https://hg.mozilla.org/integration/gaia-central/rev/3bb28013057e
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #17250 from eliperelman/bug-979396-homescreen-swipe-velocity

Bug 979396 - Converting homescreen swipe animation to be velocity-sensitive

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https://hg.mozilla.org/integration/gaia-central/rev/e6d4335cf06a
Author: Eli Perelman <eli@eliperelman.com>
Desc: Converting homescreen swipe animation to be velocity-sensitive
Bumping manifests a=b2g-bump