accessd: afs-client-accessd and friends

Add the afs-client-accessd perl script for collecting client volume
accesses, and a couple of related files.

Imported from commit 2a3bf1bdb50f526f76c2a178417b6ba9ac23a7f4 from
a site-specific OpenAFS git repo.
accessd: trace subroutine calls in debug mode
accessd: example config
accessd: RHEL 5.x msgrcv workaround option

RHEL 5.x broken msgrcv workaround. msgrcv fails supriously
on older versions of RHEL 5.x without setting the errno. strace
shows ERESTARTNOHAND errors.
accessd: option to get the fqdn of the host

Depending on how the name resolution is configured, hostname
will return the short name or the fqdn. Set USE_FQDN to always
get the FQDN, making the names consistent.