Don't set link_info.executable for "ld -r"

Don't set link_info.executable for "ld -r"

This patch changes "ld -r" not to set link_info.executable.  It
removes !info->relocatable check for info->executable and adds it
for !info->executable in elflink.c.

bfd/

	* elflink.c (elf_link_add_object_symbols): Remove
	!info->relocatable check for info->executable.  Add
	!info->relocatable check for !info->executable.
	(elf_link_output_extsym): Remove
	!info->relocatable check for info->executable.

ld/

	* lexsup.c (parse_args): Don't set link_info.executable to
	TRUE for link_info.relocatable.