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

========

https://hg.mozilla.org/integration/gaia-central/rev/356c835ebdd8
Author: Ben Kelly <bkelly@mozilla.com>
Desc: Merge pull request #13873 from wanderview/contacts-revoke-url

Bug 941001: Call revokeObjectURL() on contact imgs.  r=jmcf

========

https://hg.mozilla.org/integration/gaia-central/rev/10b4d63e6af8
Author: Ben Kelly <ben@wanderview.com>
Desc: Bug 941001: Call revokeObjectURL() on contact imgs