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

========

https://hg.mozilla.org/integration/gaia-central/rev/fff7213866b5
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Merge pull request #20289 from pivanov/bug-1023140

Bug 1023140 - [Email] Missing images

========

https://hg.mozilla.org/integration/gaia-central/rev/1695c47d39f2
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 1023140 - [Email] Missing images
Bumping manifests a=b2g-bump