Remove need to clear obj_coff_keep_syms in coff object_p

Remove need to clear obj_coff_keep_syms in coff object_p

	* coffgen.c (coff_real_object_p): Don't clear obj_coff_keep_syms
	or obj_coff_keep_strings here.
	(coff_get_normalized_symtab): Free external syms directly.
	* xcofflink.c (xcoff_link_input_bfd): Restore obj_coff_keep_syms
	on error exit path.