Fixing build with gcc 4.5

http://bugs.gentoo.org/show_bug.cgi?id=318581

--- src/ppdfile.cpp
+++ src/ppdfile.cpp
@@ -282,7 +282,7 @@
  * Opérateur d'assignation
  * Assignment operator
  */
-void PPDFile::Value::operator = (const PPDFile::Value::Value &val)
+void PPDFile::Value::operator = (const PPDFile::Value &val)
 {
     if (_preformatted)
         delete[] _preformatted;