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

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https://hg.mozilla.org/integration/gaia-central/rev/d7baff8ad5ab
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc:  Bug 966729 - Fix typo to really disable test_privileged_app_contacts_prompt test
Bumping manifests a=b2g-bump