Modify AddStdCatalog to use the versioned wxstd30-gtk3.mo.

--- a/src/common/translation.cpp
+++ b/src/common/translation.cpp
@@ -1458,7 +1458,7 @@ wxArrayString wxTranslations::GetAvailableTranslations(const wxString& domain) c
 
 bool wxTranslations::AddStdCatalog()
 {
-    if ( !AddCatalog(wxS("wxstd")) )
+    if ( !AddCatalog(wxS("wxstd30-gtk3")) )
         return false;
 
     // there may be a catalog with toolkit specific overrides, it is not
