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

========

https://hg.mozilla.org/integration/gaia-central/rev/b0dd079e5c26
Author: Rex KM Lee <rexboy@mozilla.com>
Desc: Merge pull request #11119 from rexboy7/fixhd-comm-r2-master

Bug 896381 - @1.5x assets update for communcation apps (FTU, Dialer, Contacts), round2

========

https://hg.mozilla.org/integration/gaia-central/rev/d242d471dbba
Author: Rex Lee <rexboy@mozilla.com>
Desc: Bug 896381 - @1.5x assets update for communcation apps (FTU, Dialer, Contacts), round2