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

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https://hg.mozilla.org/integration/gaia-central/rev/5c15f60dd718
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Merge pull request #21393 from tauzen/Bug1027568

Bug 1027568 - [NFC] Move checks for handover records from NfcManager to NfcHandoverManager, r=gweng

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https://hg.mozilla.org/integration/gaia-central/rev/e1e2627ee2f0
Author: Krzysztof Mioduszewski <kmioduszewski@gmail.com>
Desc: Bug 1027568 - [NFC] Move checks for handover records from NfcManager to NfcHandoverManager
Bumping manifests a=b2g-bump