coff_get_normalized_symtab bfd_release

We can't free "internal" on errors, since bfd_coff_swap_sym_in may
call bfd_alloc.  For example, _bfd_XXi_swap_sym_in may even create new
sections, which use bfd_alloc'd memory.  If "internal" is freed, all
more recently bfd_alloc'd memory is also freed.

	* coffgen.c (coff_get_normalized_symtab): Don't bfd_release on
	error.