sca: obey server_address param at subscription replies

modules/sca/doc/sca_admin.xml

@@ -288,7 +288,7 @@ modparam("sca", "onhold_bflag", 15)
 		<title><varname>server_address</varname> (string)</title>
 		<para>
 		The server address which will become the value of Contact header filed
-		for NOTIFY messages.
+		for reply messages.
 		</para>
 		<para>
 		<emphasis>

modules/sca/sca_subscribe.c

@@ -1377,7 +1377,12 @@ int sca_subscription_reply(sca_mod *scam, int status_code, char *status_msg,
 		extra_headers.len = len;
 
 		SCA_STR_APPEND_CSTR(&extra_headers, "Contact: ");
-		SCA_STR_APPEND(&extra_headers, &REQ_LINE(msg).uri);
+		if (sca->cfg->server_address != NULL) {
+			SCA_STR_APPEND( &extra_headers, sca->cfg->server_address);
+		}
+		else {
+			SCA_STR_APPEND( &extra_headers, &REQ_LINE( msg ).uri );
+		}
 		SCA_STR_APPEND_CSTR(&extra_headers, CRLF);
 
 		SCA_STR_COPY_CSTR(&extra_headers,