Remove testtools.main() call from tests

There is no testtools.main() at all (this was a
unittest.main() before). Let's remove this unused
and non-working code.

The following code can be used if someone needs
to start tests manually:

    python -m unittest <test_file.py>

Change-Id: Id5162ac73825584df6c23dbe68786ff3355fc6ae

tests/functional/test_swiftclient.py

@@ -17,7 +17,6 @@ import os
 import testtools
 import time
 import types
-import unittest
 from io import BytesIO
 
 from six.moves import configparser
@@ -284,7 +283,3 @@ class TestFunctional(testtools.TestCase):
     def test_get_capabilities(self):
         resp = self.conn.get_capabilities()
         self.assertTrue(resp.get('swift'))
-
-
-if __name__ == '__main__':
-    unittest.main()

tests/unit/test_multithreading.py

@@ -341,7 +341,3 @@ class TestMultiThreadingManager(ThreadTestCase):
         ], list(err_stream.readlines()))
 
         self.assertEqual(3, thread_manager.error_count)
-
-
-if __name__ == '__main__':
-    testtools.main()

tests/unit/test_swiftclient.py

@@ -1148,7 +1148,3 @@ class TestCloseConnection(MockHttpTest):
         conn.close()
         self.assertEqual(http_conn_obj.isclosed(), True)
         self.assertEqual(conn.http_conn, None)
-
-
-if __name__ == '__main__':
-    testtools.main()