centos5环境下离线安装yum rpm包

RedHat的yum源替换为CentOS， 需要已经安装了yum python-urlgrabber-3.1.0-6.el5.noarch.rpm、yum-3.2.22-39.el5.centos.noarch.rpm、yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm、yum-metadata-parser-1.1.2-3.el5.centos.x86_64.rpm、yum-updatesd-0.9-2.el5.noarch.rpm、yum-utils-1.1.16-21.el5.centos.noarch.rpm