[commit/hpux] delete hpux_pid_to_str (unused)

[Mark Kettenis]

> From: Joel Brobecker <brobecker@adacore.com>
> Date: Thu, 13 Jan 2011 19:02:08 -0500
> 
> This is something that Tom noticed, and told me about by email.
> 
> This function is unused, and the default formatting routine does
> just fine, I think.   On pa-hpux:
> 
>         [New process 12565, lwp 2513]
>         [New process 12565, lwp 2514]

Hmm, actually I think hpux-thread.c is only relevant for the userland
threads (DCE) implementation that was available as an add-on to HP-UX
10.x.  In that context, the hpux_pid_to_str() function makes a little
bit more sense that the default.

However, I think hpux-thread.c can be considered to be dead.  The
HP-UX 10.20 systems I have access don't have the DCE stuff installed
on them, so I've never actually tested it.  I vaguely remember that
the code doesn't even compile on machines that have the DCE stuff
installed.

Any objections if I kill it?