core: removed K compat mode for onsend route

- no conditions around drop flag
- part of work to remove config compat modes, as per irc devel meeting
  discussions

onsend.h

@@ -90,8 +90,7 @@ static inline int run_onsend(struct sip_msg* orig_msg, struct dest_info* dst,
 			orig_msg->fwd_send_flags=fwd_snd_flags_bak;
 			orig_msg->rpl_send_flags=rpl_snd_flags_bak;
 			exec_post_script_cb(orig_msg, ONSEND_CB_TYPE);
-			if((sr_cfg_compat==SR_COMPAT_KAMAILIO)
-					&& (ret==0) && !(ra_ctx.run_flags&DROP_R_F)){
+			if((ret==0) && !(ra_ctx.run_flags&DROP_R_F)){
 				ret = 1;
 			}
 		} else {