Upvalues removed from 'openupval' before being closed

Undo commit c220b0a5d0: '__close' is not called again in case of
errors. (Upvalue is removed from the list before the call.) The
common error that justified that change was C stack overflows, which
are much rarer with the stackless implementation.

manual/manual.of

@@ -1630,7 +1630,6 @@ they are closed in the reverse order that they were declared.
 If there is any error while running a closing method,
 that error is handled like an error in the regular code
 where the variable was defined.
-However, Lua may call the method one more time.
 
 After an error,
 the other pending closing methods will still be called.