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

========

https://hg.mozilla.org/integration/gaia-central/rev/b59ea073ae95
Author: Dale Harvey <dale@arandomurl.com>
Desc: Bug 1097726 - Disable topsites when running integration tests. r=kgrandon
Bumping manifests a=b2g-bump