Fix the previsous commit: if the user or the password is set in the url, use

it.
(cherry picked from commit 59f41e69)
Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

modules/demux/live555.cpp

@@ -487,15 +487,15 @@ static int Connect( demux_t *p_demux )
     int  i_ret        = VLC_SUCCESS;
 
     if( p_sys->url.i_port == 0 ) p_sys->url.i_port = 554;
-    if( p_sys->url.psz_username && p_sys->url.psz_password )
+    if( p_sys->url.psz_username || p_sys->url.psz_password )
     {
         int err;
         err = asprintf( &psz_url, "rtsp://%s:%d%s", p_sys->url.psz_host,
                         p_sys->url.i_port, p_sys->url.psz_path );
         if( err == -1 ) return VLC_ENOMEM;
 
-        psz_user = strdup( p_sys->url.psz_username );
-        psz_pwd  = strdup( p_sys->url.psz_password );
+        psz_user = strdup( p_sys->url.psz_username ? p_sys->url.psz_username : "" );
+        psz_pwd  = strdup( p_sys->url.psz_password ? p_sys->url.psz_password : "");
     }
     else
     {