Merge r262690 from head to stable/9:

  When querying a process's umask via sysctl in libprocstat(), don't
  print a warning if EPERM is returned as this is an expected failure
  mode rather than error -- similar to current handling of ESRCH.
  This makes the output of 'procstat -as' vastly more palatable.

  Sponsored by: DARPA, AFRL