[dts] [PATCH V2] framework/tester closing scapy session raise exception

[Tu, Lijuan]

>   v1:
>   Sending control "^c" during  closing the scapy sessions raised the time-
>   out exception for expecting scapy prompt ">>> " return causing the failure
>   during setup.
>   Simply sending "quit" to exit scapy gratefully instead.
> 
>   v2:
>   Sending "quit()" function insteadt of "quit"
> 
> Signed-off-by: Thinh Tran <thinhtr at linux.vnet.ibm.com>

Applied with comments changed.