MFC r326738: pw(8): correct expiration period handling
and command line overrides to preconfigured values for -e, -p and -w flags. Use non-negative symbols instead of magic values in passwd_val/pw_password functions.
PR: 223431
Submitted by: Yuri Pankov (in part, patch for the manual)
Approved by: mav (mentor)
Relnotes: yes