Bumping gaia.json for 1 gaia-1_3 revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-1_3/rev/cd7b34be2351
Author: Ben Kelly <bkelly@mozilla.com>
Desc: Merge pull request #14276 from wanderview/email-scroll-jank

Bug 943498: Spread email scroll sync reflows.  r=asuth