Oops, we were being overzealous about calling nowrite().

We were doing it as soon as the other end was shut_read, but we didn't
confirm first that the other end's read buffer had been totally emptied.
This caused problems on twitter.com, at least, where they create a zillion
short-lived connections.

I don't actually need these lines at all, as it turns out, because we were
already calling nowrite() correctly on the other end after a buffer got
emptied.

ssnet.py

@@ -237,9 +237,7 @@ class Proxy(Handler):
         self.wrap2 = wrap2
 
     def pre_select(self, r, w, x):
-        if self.wrap1.shut_read: self.wrap2.nowrite()
         if self.wrap1.shut_write: self.wrap2.noread()
-        if self.wrap2.shut_read: self.wrap1.nowrite()
         if self.wrap2.shut_write: self.wrap1.noread()
         
         if self.wrap1.connect_to: