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

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https://hg.mozilla.org/integration/gaia-central/rev/dc2f18d224f4
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #21372 from KevinGrandon/bug_1033451_collection_pin_perf

Bug 1033451 - [Smart Collection] Adding collection to top is slow to draw and load

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https://hg.mozilla.org/integration/gaia-central/rev/7177b59926a9
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1033451 - [Smart Collection] Adding collection to top is slow to draw and load r=crdlc
Bumping manifests a=b2g-bump