remove stdin wrapper

[kzidane]

For some reason breaks passenger:

Traceback (most recent call last):
File "/var/lib/gems/2.5.0/gems/passenger-5.3.5/src/helper-scripts/wsgi-loader.py", line 391, in <module>
handler.main_loop()
File "/var/lib/gems/2.5.0/gems/passenger-5.3.5/src/helper-scripts/wsgi-loader.py", line 187, in main_loop
client, address = self.accept_connection()
File "/var/lib/gems/2.5.0/gems/passenger-5.3.5/src/helper-scripts/wsgi-loader.py", line 224, in accept_connection
result = select.select([self.owner_pipe, self.server.fileno()], [], [])[0]
TypeError: fileno() takes 0 positional arguments but 1 was given

Was originally added to fix #54 but that doesn't seem to be a problem in Python 3.7 at least.