Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/e31b892e3313
Author: Sherman Chen <shamenchens@users.noreply.github.com>
Desc: Merge pull request #20795 from shamenchens/Bug1028069-Remove-Scheme-Port

Bug1028069 Remove scheme and port, r=yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/be88e279a433
Author: Sherman Chen <shamen.chens@gmail.com>
Desc: Bug 1028069 - Remove Scheme and Port in build system

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https://hg.mozilla.org/integration/gaia-central/rev/974e0185c97a
Author: Jan Jongboom <janjongboom@gmail.com>
Desc: Merge pull request #20922 from comoyo/bug1025808

Bug 1025808 - Need a disabled style for the key after the new visual update. r=janjongboom

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https://hg.mozilla.org/integration/gaia-central/rev/0edb815d9acf
Author: Sébastien Blin <amarok@enconn.fr>
Desc: Bug 1025808 - Need a disabled style for the key after the new visual update
Bumping manifests a=b2g-bump