Bumping gaia.json for 2 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/4488e32f5bac
Author: Fabien Cazenave <fabien@cazenave.cc>
Desc: Merge pull request #10351 from fabi1cazenave/mmsUnknownAttachments-bug875408

Bug 875408 - [MMS] Display unknown file types, r=julienw

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https://hg.mozilla.org/integration/gaia-central/rev/aeeeaa16c55d
Author: Fabien Cazenave <fabien@cazenave.cc>
Desc: Bug 875408 - [MMS] Display unknown file types and corrupted attachments