Add ETIMEDOUT to the list of relatively benign unclean-close errnos.

tornado/iostream.py

@@ -59,7 +59,8 @@ _ERRNO_WOULDBLOCK = (errno.EWOULDBLOCK, errno.EAGAIN)
 
 # These errnos indicate that a connection has been abruptly terminated.
 # They should be caught and handled less noisily than other errors.
-_ERRNO_CONNRESET = (errno.ECONNRESET, errno.ECONNABORTED, errno.EPIPE)
+_ERRNO_CONNRESET = (errno.ECONNRESET, errno.ECONNABORTED, errno.EPIPE,
+                    errno.ETIMEDOUT)
 
 
 class StreamClosedError(IOError):