Description of problem:
Your last change in /etc/pam.d/system-auth (system-auth: skip session pam_unix 
for crond service) causes a problem which direct results in unnecessary logfile 
messages in /var/log/secure when doing ssh logins:

sshd[10085]: Accepted password for tux from 192.168.0.1 port 62900 ssh2
sshd[10087]: pam_succeed_if(sshd:session): requirement "service in crond" not 
met by user "tux"
sshd[10087]: pam_unix(sshd:session): session opened for user tux by (uid=0)

BTW, same is e.g. at "su -":
su: pam_succeed_if(su-l:session): requirement "service in crond" not met by user 
"root"
su: pam_unix(su-l:session): session opened for user root by tux(uid=500)

Version-Release number of selected component (if applicable):
pam-0.99.6.2-1

How reproducible & Steps to Reproduce:
Everytime, upgrade to pam-0.99.6.2-1, do a ssh login and have a look into
/var/log/secure log file.

Actual results:
Unnecessary log messages.

Expected results:
Silence like before...