PR22150, ld keeps a version reference for gc'd symbols

[Maciej W. Rozycki]

On Tue, 19 Sep 2017, Alan Modra wrote:

> elf_gc_sweep_symbol should run after verdefs are calculated, since
> the verdef code creates symbols for the versions.  However,
> elf_gc_sweep_symbol needs to run before verrefs so as to not emit
> useless verrefs for symbols that are gc'd.
> 
> I've also removed a _bfd_elf_link_renumber_dynsyms calls added by
> Maciej after I fussed about it when reviewing.  On further examination
> the call appears to be unnecessary.  Looking at renumber_dynsyms also
> made me realize that the test to exclude .gnu.version has been wrong
> since 2016-04-26 (git commit d5486c4372), so fix that too.

 Thanks for following up with this seemingly never-ending story.

  Maciej