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

========

https://hg.mozilla.org/integration/gaia-central/rev/ae7609835777
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #16490 from etiennesegonzac/bug-946809-ignore-multitouch-in-edge-swipe-detector

Bug 946809 - Ignore multitouch events in the edge swipe detector. r=vingtetun

========

https://hg.mozilla.org/integration/gaia-central/rev/180fb7e6c91c
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 946809 - Ignore multitouch events in the edge swipe detector.

========

https://hg.mozilla.org/integration/gaia-central/rev/7d14cb0ff28a
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #16668 from viorelaioia/bug-977052

Intermittent in test_settings_from_message

========

https://hg.mozilla.org/integration/gaia-central/rev/37a8fb62856e
Author: Viorela Ioia <viorelaioia@gmail.com>
Desc: intermittent in test_settings_from_message
Bumping manifests a=b2g-bump