serrano-common: Disable wifi background scan

 * Testing to see if battery consumption improves.

Change-Id: Ica1b9be36c0c026b5303a0ae739d5ef4afc9010f
serrano: Sync some stuff with CAF, and some minor cleanup

Change-Id: Ie93616defebc65efe1efec9e321dc2ce4d2b2991