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

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https://hg.mozilla.org/integration/gaia-central/rev/6201848a813d
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 1022459 - The marionette_js jobs do not run all marionette tests after Bug 1021706 is landed r=jlal
Bumping manifests a=b2g-bump