Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-1_3/rev/2f92a6b7a47b
Author: Ben Tian <btian@mozilla.com>
Desc: Merge pull request #16639 from bentian/bug-972142

Revert "Bug 972142 - Set camera preview style with CSS pixel values." per bug 972142 comment 24.

========

https://hg.mozilla.org/integration/gaia-1_3/rev/97f6c0a3d483
Author: Ben Tian <btian@mozilla.com>
Desc: Revert "Bug 972142 - Set camera preview style with CSS pixel values."

This reverts commit 03404b44494fcaece0631a5effab771431a72e33.
Bumping manifests a=b2g-bump