Description of problem:
Procmail is not allowed to run /bin/ls, which is needed by a standard procmail
rule.  Either this rule should not be recommended or this usage should be allowed.  

Version-Release number of selected component (if applicable):
selinux-policy-targeted-2.4.6-27.fc6
procmail-3.22-17.1

How reproducible:
every time

Steps to Reproduce:
1. add backup system to personal procmailrc according to procmailex manual page:

:0 c
backup

:0 ic
| cd backup && rm -f dummy `ls -t msg.* | sed -e 1,45d`

2. allow mail to arrive

Actual results:
avc: denied { signull } for comm="zsh" egid=500 euid=500 exe="/bin/zsh" exit=-13
fsgid=500 fsuid=500 gid=500 items=0 pid=5555
scontext=system_u:system_r:procmail_t:s0 sgid=500
subj=system_u:system_r:procmail_t:s0 suid=500 tclass=process
tcontext=system_u:system_r:procmail_t:s0 tty=(none) uid=500 

Expected results:
Since this is a standard recommended use of procmail, the use should be
permitted by default.  Alternatively, the procmail manual should have a
different example.  E.g. you could do just the same thing 

Additional info:
work around 
1. put above audit message into a file (e.g. procmail-fixme.avc)
2. audit2allow -M procmail   < procmail-fixme.avc
3. semodule -i procmail.pp