lint: remove extraneous logic for preexec_func (#2920)

`preexec_func` is still None if it is win32

Signed-off-by: q0w <43147888+q0w@users.noreply.github.com>

docker/transport/sshconn.py

@@ -62,7 +62,7 @@ def f():
             env=env,
             stdout=subprocess.PIPE,
             stdin=subprocess.PIPE,
-            preexec_fn=None if constants.IS_WINDOWS_PLATFORM else preexec_func)
+            preexec_fn=preexec_func)
 
     def _write(self, data):
         if not self.proc or self.proc.stdin.closed: