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

========

https://hg.mozilla.org/integration/gaia-central/rev/aae41b7d327b
Author: Sebastiaan de Haan <me@sebastiaandehaan.nl>
Desc: Bug 935964 - Bump gaiatest to 0.19. r=dhunt