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

========

https://hg.mozilla.org/integration/gaia-central/rev/19b3a63a63a2
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #19232 from crdlc/bug-1004989

Bug 1004989 - [Homescreen] The downloading animation is not properly around the downloading icon

========

https://hg.mozilla.org/integration/gaia-central/rev/0379fbb81138
Author: crdlc <crdlc@tid.es>
Desc: Bug 1004989 - [Homescreen] The downloading animation is not properly around the downloading icon
Bumping manifests a=b2g-bump