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

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https://hg.mozilla.org/integration/gaia-central/rev/2e722ec5c67c
Author: Ben Francis <ben@tola.me.uk>
Desc: Bug 937929 - Possible to open awesomescreen with awesomebar hidden. r=daleharvey