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

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https://hg.mozilla.org/integration/gaia-central/rev/1a7f19f338c8
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Merge pull request #16219 from Rik/wakelock-enabled-971761

Bug 971761 - Enable requestWakeLock in DEBUG builds to turn our tests gr... r=kgrandon

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https://hg.mozilla.org/integration/gaia-central/rev/7862edf5508c
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Bug 971761 - Enable requestWakeLock in DEBUG builds to turn our tests green
Bumping manifests a=b2g-bump