Unix CM: Use macros for process name and id access

Unix CM: Use macros for process name and id access

This patch uses the new osi_procname() macro to obtain the process
name for setpag() warnings on BSD and Darwin, and osi_curproc() to
obtain the process identity, simplifying the code.

Change-Id: I1f8a4d4bbcdb09eaeea3712b1fffd1aaa3cd2fa7
Reviewed-on: http://gerrit.openafs.org/1878
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Matt Benjamin <matt@linuxbox.com>
Tested-by: Derrick Brashear <shadow@dementia.org>