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

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https://hg.mozilla.org/integration/gaia-central/rev/6e3ce9f6450c
Author: Fabrice Desré <fabrice@desre.org>
Desc: Merge pull request #21889 from guilherme-pg/bug1038881-wakelock

Bug 1038881 - Use a wakelock to keep Find My Device alive when necessary...

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https://hg.mozilla.org/integration/gaia-central/rev/a562759390ef
Author: Guilherme Goncalves <guilherme.p.gonc@gmail.com>
Desc: Bug 1038881 - Use wakelocks to keep Find My Device alive.
Bumping manifests a=b2g-bump