Bumping gaia.json for 4 gaia-central revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/99fccbaf953b
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #13158 from crh0716/911701

Bug 911701 - Show data signal strength when connecting to EVDO r=alive

========

https://hg.mozilla.org/integration/gaia-central/rev/5507232168db
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 911701 - Show data signal strength when connecting to EVDO

========

https://hg.mozilla.org/integration/gaia-central/rev/529ce3503314
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #13173 from crh0716/929792

But 929792 - Add a observer on keyboard name changes r=evelyn

========

https://hg.mozilla.org/integration/gaia-central/rev/ef6f8c6ff42e
Author: Arthur Chen <crh0716@gmail.com>
Desc: But 929792 - Add a observer on keyboard name changes