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

========

https://hg.mozilla.org/integration/gaia-central/rev/6fd4c4c0074d
Author: Sherman Chen <shamen.chens@gmail.com>
Desc: Revert "Bug 1021481 - Handle app protocol for DEBUG=1 mode, with port change"

This reverts commit b3cc85ade91b0eba479fe60f6d017628d5541791.

========

https://hg.mozilla.org/integration/gaia-central/rev/b191ec1c00bb
Author: Sherman Chen <shamen.chens@gmail.com>
Desc: Revert "Bug 1028069 - Remove Scheme and Port in build system"

This reverts commit 3df12b3987e4468723956aa2a8fe0ece9f5cf692.

========

https://hg.mozilla.org/integration/gaia-central/rev/b2cb74c6657c
Author: Wilson Page <wilsonpage@me.com>
Desc: Merge pull request #20452 from wilsonpage/990482

Bug 990482 - [Camera][UX] Swipe gesture should work on camera mode switcher

========

https://hg.mozilla.org/integration/gaia-central/rev/ef20c46dddbc
Author: Wilson Page <wilsonpage@me.com>
Desc: Bug 990482 - [Camera][UX] Swipe gesture should work on camera mode switcher
Bumping manifests a=b2g-bump