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

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https://hg.mozilla.org/integration/gaia-central/rev/0d6dca3dab03
Author: Augustin Trancart <augustin.trancart@gmail.com>
Desc: Bug 918970 - display existing thread when sending a sms from contact app r=julien
Bumping manifests a=b2g-bump