Really fix data-directory/Makefile rebuilding

Oops, I botched the last patch to fix data-directory/Makefile
rebuilding, by copying the config.status line and forgetting to update
the directory name.  This one fixes the problem for real.

gdb/ChangeLog
2021-06-05  Tom Tromey  <tom@tromey.com>

	* data-directory/Makefile.in (Makefile): Use correct directory
	name.