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

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https://hg.mozilla.org/integration/gaia-central/rev/e402acba87cf
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #14636 from alivedise/bugzilla/949950/typo-gaia-apps

Bug 949950 - fix src in gaia-apps, r=davehunt

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https://hg.mozilla.org/integration/gaia-central/rev/f397343db001
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 949950 - fix src in gaia-apps

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https://hg.mozilla.org/integration/gaia-central/rev/4e4fbe820dd0
Author: Arnau <arnau@arnaumarch.com>
Desc: Merge pull request #14497 from rnowm/FB-header

Bug 946775 - [contacts][facebook] When importing contacts, blue facebook...

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https://hg.mozilla.org/integration/gaia-central/rev/3a8d41c1364c
Author: rnowm <arnau@arnaumarch.com>
Desc: Bug 946775 - [contacts][facebook] When importing contacts, blue facebook header has wrong tapped color

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