iotests: 'new' module replacement in 169

iotest 169 uses the 'new' module to add methods to a class.  This module
no longer exists in Python 3.  Instead, we can use a lambda.  Best of
all, this works in 2.7 just as well.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NEduardo Habkost <ehabkost@redhat.com>
Reviewed-by: NCleber Rosa <crosa@redhat.com>
Message-Id: <20181022135307.14398-8-mreitz@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

tests/qemu-iotests/169

@@ -23,7 +23,6 @@ import iotests
 import time
 import itertools
 import operator
-import new
 import re
 from iotests import qemu_img
 
@@ -204,7 +203,7 @@ class TestDirtyBitmapMigration(iotests.QMPTestCase):
 
 def inject_test_case(klass, name, method, *args, **kwargs):
     mc = operator.methodcaller(method, *args, **kwargs)
-    setattr(klass, 'test_' + method + name, new.instancemethod(mc, None, klass))
+    setattr(klass, 'test_' + method + name, lambda self: mc(self))
 
 for cmb in list(itertools.product((True, False), repeat=4)):
     name = ('_' if cmb[0] else '_not_') + 'persistent_'