chan_sip: No BYE message sent after INVITE with Replaces

Setting channel state DOWN is an unnecessary step that was
only being done in handle_invite_replaces().  This changes
that by removing the call and reducing locking.

(closes issue ASTERISK-23010)
Reported by: Ryan Tilton
Review: https://reviewboard.asterisk.org/r/3116/
........

Merged revisions 405486 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@405487 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -24893,12 +24893,11 @@ static int handle_invite_replaces(struct sip_pvt *p, struct sip_request *req, st
 	if (ast_do_masquerade(replacecall)) {
 		ast_log(LOG_WARNING, "Failed to perform masquerade with INVITE replaces\n");
 	}
-	ast_channel_lock(c);
 	if (earlyreplace || oneleggedreplace ) {
+		ast_channel_lock(c);
 		ast_channel_hangupcause_set(c, AST_CAUSE_SWITCH_CONGESTION);
+		ast_channel_unlock(c);
 	}
-	ast_setstate(c, AST_STATE_DOWN);
-	ast_channel_unlock(c);
 	/* c and c's tech pvt must be unlocked at this point for ast_hangup */
 	ast_hangup(c);