rconn: Simplify rconn_send() semantics.

Before this patch, rconn_send() would delete 'b' on success, and
not on error.  This is confusing and error-prone.  This patch
causes rconn_send() to always delete 'b'.

Signed-off-by: Ethan Jackson <ethan@nicira.com>

lib/learning-switch.c

@@ -178,7 +178,6 @@ lswitch_create(struct rconn *rconn, const struct lswitch_config *cfg)
         if (error) {
             VLOG_INFO_RL(&rl, "%s: failed to queue default flows (%s)",
                          rconn_get_name(rconn), strerror(error));
-            ofpbuf_delete(msg);
         }
     }