Fix setting wxPG_PROP_STRING_PASSWORD attribute

For built-in attributes (like wxPG_PROP_STRING_PASSWORD) wxPGProperty::DoSetAttribute() should return true to give the option (controlled by wxPG_EX_WRITEONLY_BUILTIN_ATTRIBUTES style) to prevent the attribute from being stored into property's attribute storage.

src/propgrid/props.cpp

@@ -145,9 +145,9 @@ bool wxStringProperty::DoSetAttribute( const wxString& name, wxVariant& value )
         m_flags &= ~(wxPG_PROP_PASSWORD);
         if ( value.GetLong() ) m_flags |= wxPG_PROP_PASSWORD;
         RecreateEditor();
-        return false;
+        return true;
     }
-    return true;
+    return false;
 }
 
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