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

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https://hg.mozilla.org/integration/gaia-central/rev/34308e903e51
Author: Julien Wajsberg <felash@gmail.com>
Desc: iBug 1050729 - Reduce overpaint of the sms app r=julien
Bumping manifests a=b2g-bump