Revert "tests: migration/guestperf Python 2.6 argparse compatibility"

This reverts commit 0ea47d0f36.

scripts/argparse.py was removed from the tree, so we don't
need this hack anymore.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180618225131.13113-4-ehabkost@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

tests/migration/guestperf/shell.py

@@ -19,14 +19,12 @@ from __future__ import print_function
 #
 
 
-import os
-import os.path
-import sys
-sys.path.append(os.path.join(os.path.dirname(__file__),
-                             '..', '..', '..', 'scripts'))
 import argparse
 import fnmatch
+import os
+import os.path
 import platform
+import sys
 import logging
 
 from guestperf.hardware import Hardware