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

========

https://hg.mozilla.org/integration/gaia-1_3/rev/92c4784b8e74
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #16938 from crdlc/bug-978011

Bug 978011 - Unload properly Image Loader when syncing/importing
Bumping manifests a=b2g-bump