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

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https://hg.mozilla.org/integration/gaia-central/rev/949d89b5cf56
Author: Dale  Harvey <dale@arandomurl.com>
Desc: Merge pull request #11379 from benfrancis/840210

Bug 840210 - search engine must be customizable at build time. r=daleharvey

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https://hg.mozilla.org/integration/gaia-central/rev/945123957fe8
Author: Ben Francis <ben@tola.me.uk>
Desc: Bug 840210 - search engine must be customizable at build time