libpkg: remove dead file

[ifreund]

This file has been dead since bdd5af5.

Sponsored by: The FreeBSD Foundation

[kevemueller]

Hi Isaac, I had left the file around as not all of the functionality in it was incorporated (yet) in the new Mach-O code. Was delaying the libs functions for Mach-O in expectation that there will be a refactoring of shlibs provides/requires.
I might be just adding Mach-O with current libs functionality and then removing pkg_macho.c
Obviously I can retrieve this file from a previous commit, but I think it is clearer to remove the file once all of its functionality is there in the new (current) pkg_abi_macho.c.

[ifreund]

This file's continued existence in the source tree confused me today when grepping for certain functions/variables landed me in this now dead code. As I was not familiar with the status of your work on macho support, it took me a bit to realize that this code was in fact dead.

In my opinion, leaving dead code in the source tree causes more confusion than its worth. I would prefer using an issue on the issue tracker to keep track of any functionality that is missing from the new pkg_abi_macho.c implementation.

I will of course defer to you and bapt though, I'm not personally working on macho related stuff.