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

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https://hg.mozilla.org/integration/gaia-central/rev/8994e503ee40
Author: Eitan Isaacson <eitan@monotonous.org>
Desc: Bug 1014859 - [gaia-switch] Put click listener on container label. r=kgrandon
Bumping manifests a=b2g-bump