oeqa/utils/qemurunner.py: Add missing sys module

This adds the missing sys module used by the child process
to exit. It seems the exception was cached in testimage and
selftest. It seems nobody noticed this because the module
is only used for sys.exit().

(From OE-Core rev: 66f66d1d763ff7bbaab9e8fcdf7fc882f2dfbb13)

Signed-off-by: Mariano Lopez <mariano.lopez@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/utils/qemurunner.py

@@ -7,6 +7,7 @@
 
 import subprocess
 import os
+import sys
 import time
 import signal
 import re