remove persist.sys.usb.config override

The variable persist.sys.usb.config is no longer honored by the framework,
and it's presence causes unnecessary toggling of the USB driver, which
disonnects ADB and makes the device's connection unstable.

Delete it.

Bug: 21404762
Bug: 18905620
Change-Id: Iaeded8a7617e9d787480b91387ca993d4e0a786c
1 file changed