Description of problem:

Actual search string is 
[root@srv12act services]# egrep "[a-zA-Z0-9]+: client=([^ ]*\[[^ ]*\])$" /var/lo
803
But there can be some extra space at the end : 
[root@srv12act services]# egrep "[a-zA-Z0-9]+: client=([^ ]*\[[^ ]*\])\s*$"
/var/log/maillog|wc -l
215878


Version-Release number of selected component (if applicable):
Name        : logwatch                 
Version     : 5.2.2                  
Release     : 1.EL4.1                      

How reproducible:
Use any Mail relay logs

Steps to Reproduce:
1. run logwatch on postfix logs
2.
3.
  
Actual results:
4M of resulting mail

Expected results:
far less 

Additional info:
Proposed patch in unified format