Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-1_4/rev/8254fbf77ccd
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #21909 from crh0716/1038496

Bug 1038496 - Re-enable radio when rild crashes r=alive
Bumping manifests a=b2g-bump