test: fix bugs (scp -l and trap ERR)

This patch fixes bugs:

- '-l' option for scp is different from that of ssh, so remove
  this option from the common param for scp and ssh.

- trap ERR was not executed, so replace it by trap EXIT

Change-Id: Id50ff29656fa100f420ae9ccc7a8a19a65a941c8
Signed-off-by: Ryota MIBU <r-mibu@cq.jp.nec.com>
(cherry picked from commit eed432fa413d3afeecdd65ef0f73559920012df9)