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

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https://hg.mozilla.org/integration/gaia-central/rev/f5dc746df1ae
Author: Julien Wajsberg <felash@gmail.com>
Desc: Revert "Bug 920546 - [Messages] Short-term fixes for the recipient panel r=julienw"

This reverts commit 7c5b6e746b800b3747c3be6eae67ad3948891497.