pcp

pmie_daily - assorted minor fixups

• handling of realpath equivalent in _unsymlink_path() was not
  strictly correct, and failed on Mac OS X where /tmp is really
  a symlink to /private/tmp
• the test for existence of a process used /proc/pinfo/ or
  /proc/ ... the exit status from ps -p is a much more
  portable way to do this
• improved diagnostics with -VV to help track matching running
  processes against the control file and the contents of
  $PCP_TMP_DIR/pmie