Simplify resetting of delay_close and delay_tunnel_reason
When delay_close and delay_tunnel_reason were added in
4fb6ff70, the mainloop would only reset them
in specific branches (e.g. if the connection termination had been initiated
by OC_CMD_CANCEL
or OC_CMD_PAUSE
.
This ensures that they will be reset on each iteration, thereby making the "spin forever" case more idiot-proof. (With me being the probable idiot.)