test_ipalib.test_frontend: Port unbound method tests to Python 3

Python 3 uses plain function objects instead of unbound methods.
So, what was Class.method.__func__ is now just Class.method.

Reviewed-By: Tomas Babej <tbabej@redhat.com>

ipatests/test_ipalib/test_frontend.py

@@ -648,7 +648,10 @@ class test_Command(ClassChecker):
         (api, home) = create_test_api(in_server=True)
         api.finalize()
         o = my_cmd(api)
-        assert o.run.__func__ is self.cls.run.__func__
+        if six.PY2:
+            assert o.run.__func__ is self.cls.run.__func__
+        else:
+            assert o.run.__func__ is self.cls.run
         out = o.run(*args, **kw)
         assert ('execute', args, kw) == out
 
@@ -656,7 +659,10 @@ class test_Command(ClassChecker):
         (api, home) = create_test_api(in_server=False)
         api.finalize()
         o = my_cmd(api)
-        assert o.run.__func__ is self.cls.run.__func__
+        if six.PY2:
+            assert o.run.__func__ is self.cls.run.__func__
+        else:
+            assert o.run.__func__ is self.cls.run
         assert ('forward', args, kw) == o.run(*args, **kw)
 
     def test_messages(self):
@@ -688,14 +694,20 @@ class test_Command(ClassChecker):
         (api, home) = create_test_api(in_server=True)
         api.finalize()
         o = my_cmd(api)
-        assert o.run.__func__ is self.cls.run.__func__
+        if six.PY2:
+            assert o.run.__func__ is self.cls.run.__func__
+        else:
+            assert o.run.__func__ is self.cls.run
         assert {'name': 'execute', 'messages': expected} == o.run(*args, **kw)
 
         # Test in non-server context
         (api, home) = create_test_api(in_server=False)
         api.finalize()
         o = my_cmd(api)
-        assert o.run.__func__ is self.cls.run.__func__
+        if six.PY2:
+            assert o.run.__func__ is self.cls.run.__func__
+        else:
+            assert o.run.__func__ is self.cls.run
         assert {'name': 'forward', 'messages': expected} == o.run(*args, **kw)
 
     def test_validate_output_basic(self):