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

========

https://hg.mozilla.org/integration/gaia-central/rev/6a6778c8ff4a
Author: James Lal <james@lightsofapollo.com>
Desc: Merge pull request #19585 from lightsofapollo/bin-ci-no-after

Bug 1015059 - Only run gaia_ui_tests after_script on travis ci

========

https://hg.mozilla.org/integration/gaia-central/rev/06b1cb76c1d4
Author: James Lal <james@lightsofapollo.com>
Desc: Bug 1015059 - Only run gaia_ui_tests after_script on travis ci
Bumping manifests a=b2g-bump