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

========

https://hg.mozilla.org/integration/gaia-central/rev/8af2f10fe521
Author: Germán Toro del Valle <gtorodelvalle@gmail.com>
Desc: Merge pull request #15680 from gtorodelvalle/contacts-bug-960525-undefined-last-name

Bug 960525 - [Contacts] undefined as contact's last name after merging

========

https://hg.mozilla.org/integration/gaia-central/rev/af7449ed81cc
Author: Germán Toro del Valle <gtorodelvalle@gmail.com>
Desc: Bug 960525 - [Contacts] undefined as contact's last name after merging
Bumping manifests a=b2g-bump