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

========

https://hg.mozilla.org/integration/gaia-central/rev/e96d5a01194d
Author: Chris Jones <cjones.bugs@gmail.com>
Desc: Merge pull request #24453 from cgjones/board-gaia-make-flags

Bug 1071939: Initialize GAIA_MAKE_FLAGS with new var BOARD_GAIA_MAKE_FLA...

========

https://hg.mozilla.org/integration/gaia-central/rev/6d5ca3d2c882
Author: Chris Jones <cjones.bugs@gmail.com>
Desc: Bug 1071939: Initialize GAIA_MAKE_FLAGS with new var BOARD_GAIA_MAKE_FLAGS. r=ochameau
Bumping manifests a=b2g-bump