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

========

https://hg.mozilla.org/integration/gaia-central/rev/5cc807be4ece
Author: George <georgeiscoming@gmail.com>
Desc: Merge pull request #11985 from cctuan/911676

Bug 911676 - check navigator.mozTelephony statements robustness

========

https://hg.mozilla.org/integration/gaia-central/rev/171659274531
Author: cctuan <georgeiscoming@gmail.com>
Desc: Bug 911676 - check navigator.mozTelephony statements robustness