Fix minor errors in hooks.pod
Fix minor errors in hooks.pod

While writing a plugin for our new spamfilter implementation I noticed
some minor error in the documentation. From the documentation it
sounds like the hook_ok and hook_deny hooks get the previous hook as
parameter.. The truth is: it is the previous plugin.

sieutruc/qpsmtpd,msimerson/qpsmtpd,smtpd/qpsmtpd,salvis/qpsmtpd,sieutruc/qpsmtpd,msimerson/qpsmtpd,sieutruc/qpsmtpd,smtpd/qpsmtpd,priyadi/qpsmtpd,priyadi/qpsmtpd,salvis/qpsmtpd,priyadi/qpsmtpd