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

========

https://hg.mozilla.org/integration/gaia-central/rev/a70a7687d22b
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #18478 from KevinGrandon/bug_998810_homescreen_alarms_permission

Bug 998810 - [Homescreen] remove alarms permission from manifest

========

https://hg.mozilla.org/integration/gaia-central/rev/078344388a41
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 998810 - [Homescreen] remove alarms permission from manifest r=ran
Bumping manifests a=b2g-bump