Removes warning for one path not returning a value.

* Default returns empty string even though this path is never reached.

src/fedex_plus/classes_misc.c

@@ -612,6 +612,7 @@ GetTypeDescriptorName( Type t ) {
             printf( "Error in %s, line %d: type %d not handled by switch statement.", __FILE__, __LINE__, TYPEget_body( t )->type );
             abort();
     }
+    return "";
 }
 
 int