Don't change the default symbol for relocatable link

Don't change the default symbol for relocatable link

We should change the default symbol for the versioned symbol only when
not performing a relocatable link.

bfd/

	PR ld/18735
	* elflink.c (_bfd_elf_add_default_symbol): Add the default
	symbol if not performing a relocatable link.
	(elf_link_add_object_symbols): Adjust the default symbol if
	not performing a relocatable link.

ld/testsuite/

	PR ld/18735
	* ld-elf/pr18735.d: New file.
	* ld-elf/pr18735.s: Likewise.