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

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https://hg.mozilla.org/integration/gaia-central/rev/5c5ece219355
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 981711 - [Messages] Bug 947180 broke the SIM switch r=schung

This patch restores the SIM switching functionality using the iccId property.
Bumping manifests a=b2g-bump