Change meaning miss_send_len of set config and max_len field of output

action

If "max_send_len" (or the "max_len" field for the controller output
action) is zero, then send a packet-in with zero bytes of the packet
data.

include/openflow/openflow.h

@@ -341,8 +341,7 @@ enum ofp_action_type {
 
 /* Action structure for OFPAT_OUTPUT, which sends packets out 'port'.
  * When the 'port' is the OFPP_CONTROLLER, 'max_len' indicates the max
- * number of bytes to send.  A 'max_len' of zero means the entire packet
- * should be sent. */
+ * number of bytes to send. */
 struct ofp_action_output {
     uint16_t type;                  /* OFPAT_OUTPUT. */
     uint16_t len;                   /* Length is 8. */