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

========

https://hg.mozilla.org/integration/gaia-1_4/rev/2d8208e4a17e
Author: DouglasSherk <github@sherk.me>
Desc: Bug 1030912 - Make BluetoothHelper listen for mozBluetooth events. r=ianliu
Bumping manifests a=b2g-bump