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

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https://hg.mozilla.org/integration/gaia-central/rev/19aba7aaa442
Author: Yoshi Huang <allstars.chh@mozilla.com>
Desc: Merge pull request #16169 from allstarschh/Bug970238

Bug970238

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https://hg.mozilla.org/integration/gaia-central/rev/d31f217bd198
Author: allstars.chh <allstars.chh@gmail.com>
Desc: Bug 970238 - NFC: System app always send NFC_HW_STATE_DISABLE_DISCOVERY
to Gecko
Bumping manifests a=b2g-bump