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

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https://hg.mozilla.org/integration/gaia-central/rev/f2f888d39909
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #15270 from KevinGrandon/bug_959285_search_abort_requests

Bug 959285 - [Search] Abort in-progress provider requests

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https://hg.mozilla.org/integration/gaia-central/rev/fbf0bee9d05e
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 959285 - [Search] Abort in-progress provider requests r=amirn