Really fix compilation with old SIP (tool for generating bindings)

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>

git-svn-id: http://svn.berlios.de/svnroot/repos/sems/trunk@1775 8eb893ce-cfd4-0310-b710-fb5ebe64c474

apps/py_sems/sip/string.sip

@@ -23,7 +23,7 @@ using std::string;
              return 0;
          }
 #if  SIP_VERSION < 0x040901
-         *sipCppPtr = (std::string *)sipForceConvertToType(sipPy, sipType_string, NULL, SIP_NO_CONVERTORS, NULL, sipIsErr);
+         *sipCppPtr = (std::string *)sipForceConvertTo_string(sipPy, sipIsErr);
 #else
          *sipCppPtr = (std::string *)sipForceConvertToType(sipPy, sipType_string, NULL, SIP_NO_CONVERTORS, NULL, sipIsErr);
 #endif