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

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https://hg.mozilla.org/integration/gaia-central/rev/e8a74882ae37
Author: Fabien Cazenave <fabien@mozilla.com>
Desc: Merge pull request #16742 from fabi1cazenave/fdnMessages-bug976416

Bug 976416 - [FDN] enable the + sign in the keypad, r=vingtetun

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https://hg.mozilla.org/integration/gaia-central/rev/0addd92dd3ed
Author: Fabien Cazenave <fabien@cazenave.cc>
Desc: Bug 976416 - [FDN] enable the + sign in the keypad, r=vingtetun
Bumping manifests a=b2g-bump