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

========

https://hg.mozilla.org/integration/gaia-central/rev/5c72f184f51d
Author: Greg Weng <snowmantw@gmail.com>
Desc: Merge pull request #21670 from snowmantw/issue1037027

Bug 1037027 - [Lockscreen] notifications can overlap the date on the loc...

========

https://hg.mozilla.org/integration/gaia-central/rev/8ca16caf0451
Author: Greg Weng <snowmantw@gmail.com>
Desc: Bug 1037027 - [Lockscreen] notifications can overlap the date on the lockscreen
Bumping manifests a=b2g-bump