CLEANUP: stream: Remove bogus loop in conn_si_send_proxy

The if-statement was converted into a while-loop in
7fe45698f58a53dda9182a5970a2ea4bda9f92fe to handle EINTR.

This special handling was later replaced in
0a03c0f022faf2773995fc8b9d14256c8a306e5a by conn_sock_send.

The while-loop was not changed back and is not unconditionally
exited after one iteration, with no `continue` inside the body.

Replace by an if-statement.
1 file changed