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

========

https://hg.mozilla.org/integration/gaia-central/rev/23c17f5b65cd
Author: Ben Kelly <bkelly@mozilla.com>
Desc: Merge pull request #14493 from rnowm/contacts-add-oh

Bug 947819 - [Contacts] add overflow: hidden to contcats list r=jmcf

========

https://hg.mozilla.org/integration/gaia-central/rev/38f9d9acb28a
Author: rnowm <arnau@arnaumarch.com>
Desc: Bug 947819 - [Contacts] add overflow: hidden to contcats list