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

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https://hg.mozilla.org/integration/gaia-central/rev/c3d40600c009
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Merge pull request #20009 from pivanov/bug-1020228

Bug 1020228 - [Lockscreen] - @2.25x icon scale

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https://hg.mozilla.org/integration/gaia-central/rev/5b6359112458
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 1020228 - [Lockscreen] - @2.25x icon scale
Bumping manifests a=b2g-bump