[PATCH] cron: Fix parsing of '0' and non-alphanumerics in steps

[Matthew Dillon]

:
:With an entry with "*/0", cron will eat up all CPU, which could be solved w=
:ith
:attached patch. (essentially same as FreeBSD PR/68683)
:
:Obtained from: OpenBSD
:
:Cheers,
:--=20
:Xin LI <delphij frontfree net>	http://www.delphij.net/

    Committed, thanks!

					-Matt