Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/9f198e278525
Author: Ben Francis <ben@tola.me.uk>
Desc: Bug 1000678 - Don't initiate NFC sharing when on the browser start page. r=daleharvey
Bumping manifests a=b2g-bump