Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/6178c4903bdd
Author: Dale Harvey <dale@arandomurl.com>
Desc: Bug 1009401 - Update home2 rocketbar styles to match visual refresh. r=kgrandon,alive

========

https://hg.mozilla.org/integration/gaia-central/rev/371a6645973d
Author: crdlc <crdlc@tid.es>
Desc: Bug 1015895 - Use gaia-confirm component in vertical homescreen r=kgrandon

========

https://hg.mozilla.org/integration/gaia-central/rev/72b3ae0e19c2
Author: Florin Strugariu <bebef_1987@yahoo.com>
Desc: Merge pull request #19550 from chirarobert/unxfail_unlock_to_camera

Bug 1014590 - Unxfail test_lockscreen_unlock_to_camera.py

========

https://hg.mozilla.org/integration/gaia-central/rev/127b6b469f32
Author: chirarobert <robert.chira@softvision.ro>
Desc: Bug 1014590 - Unxfail test_lockscreen_unlock_to_camera.py
Bumping manifests a=b2g-bump