check for null qrealm too.

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@3405 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/endpoints/mod_sofia/mod_sofia.c

@@ -4160,7 +4160,7 @@ static void sip_r_register(int status,
 	duprealm = strdup(realm);
 	qrealm = duprealm;
 	
-	while(*qrealm && *qrealm == '"') {
+	while(qrealm && *qrealm && *qrealm == '"') {
 		qrealm++;
 	}
 	if ((p = strchr(qrealm, '"'))) {