Unbreak the storing of registrations for restart

The fix for issue 18882 broke retrieving non-realtime peers from the ast_db
on restart/reload. This patch tries to unbreak things while leaving the intent
of the original fix intact.
(closes issue #19318)
Reported by: remiq
Patches: 
      diff.txt uploaded by twilson (license 396)
Tested by: lmadsen, remiq


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@319552 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -26740,7 +26740,7 @@ static struct sip_peer *build_peer(const char *name, struct ast_variable *v, str
 		sip_cfg.allowsubscribe = TRUE;	/* No global ban any more */
 	}
 	/* If read-only RT backend, then refresh from local DB cache */
-	if (peer->host_dynamic && !sip_cfg.peer_rtupdate) {
+	if (peer->host_dynamic && (!peer->is_realtime || !sip_cfg.peer_rtupdate)) {
 		reg_source_db(peer);
 	}