fix test__wsgi.py to work with the new wsgi_test.py

greentest/test__wsgi.py

 from gevent import wsgi
+import wsgi_test
 from wsgi_test import *
 
-del TestHttps, TestChunkedApp, TestBigChunks
+del TestHttps
+
+wsgi_test.server_implements_chunked = False
 
 TestCase.get_wsgi_module = lambda *args: wsgi