Bumping gaia.json for 3 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/1ffe167e95d4
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 966915 - Rocketbar search results are including contacts, but shouldn't be r=daleharvey

========

https://hg.mozilla.org/integration/gaia-central/rev/0686cac578bb
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #15908 from viorelaioia/bug_966968

Bug 966968 - Enable test_lockscreen_unlock_to_emergency_call_screen.py on Travis

========

https://hg.mozilla.org/integration/gaia-central/rev/3bb7977e0565
Author: Viorela Ioia <viorelaioia@gmail.com>
Desc: Bug 966968 - Enable test_lockscreen_unlock_to_emergency_call_screen.py on Travis
Bumping manifests a=b2g-bump