So what you can do if you want since it is only a man page it is saying is a conflict.. Download the perl-Apache-SizeLimit rpm and force the install
wget http://apt.sw.be/redhat/el6/en/i386/rpmforge/RPMS/perl-Apache-SizeLimit-0.92-1.el6.rf.noarch.rpm
rpm -ivh --force perl-Apache-SizeLimit-0.92-1.el6.rf.noarch.rpm