Bumping gaia.json for 3 gaia-1_2 revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-1_2/rev/f23421a8c61a
Author: Bob Silverberg <bob.silverberg@gmail.com>
Desc: Merge pull request #13384 from s-dehaan/919615

Bug 919615 - PR for missing persona test.

========

https://hg.mozilla.org/integration/gaia-1_2/rev/04b05fb2764c
Author: Sebastiaan de Haan <me@sebastiaandehaan.nl>
Desc: Bug 919615: [v1.2] PR to move a missing persona test to branch v1.2

========

https://hg.mozilla.org/integration/gaia-1_2/rev/cb49dda6f778
Author: Edwin Wong <edwong@mozilla.com>
Desc: Bug 919615 - PR for missing persona test.

Conflicts:
	tests/python/gaia-ui-tests/gaiatest/apps/ui_tests/app.py
	tests/python/gaia-ui-tests/setup.py