tdeio/KDirLister: add url validity check

Before 0756aab51 and 4d6667159 this validity check was done for all URLs
inside KDirListerCache::listDir(). But since those two commits the result
of this check for remote URLs is impossible to propagate to the user. So
implicit check is in order.

Signed-off-by: Alexander Golubev <fatzer2@gmail.com>

tdeio/tdeio/kdirlister.cpp

@@ -1946,6 +1946,10 @@ bool KDirLister::openURL( const KURL& _url, bool _keep, bool _reload )
 
   d->changes = NONE;
 
+  if ( !validURL( _url ) ) {
+    return false;
+  }
+
   // Some ioslaves like media:/ or home:/ can provide a local url istead of a remote one
   // If a local path is available, monitor that instead of the given remote URL...
   if (!_url.isLocalFile()) {