CI: add missing import

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

ci-scripts/sshconnection.py

@@ -35,6 +35,7 @@ import pexpect          # pexpect
 import logging
 import time             # sleep
 import re
+import sys
 
 #-----------------------------------------------------------
 # Class Declaration