Update centos.ipxe

src/centos.ipxe

@@ -11,7 +11,7 @@ set os CentOS
 set ksdevice eth0
 menu ${os} - ${arch} - Image Sig Checks: [${img_sigs_enabled}]
 item 7.2.1511 ${os} 7.2
-item 6.7 ${os} 6.8
+item 6.8 ${os} 6.8
 isset ${osversion} || choose osversion || goto linux_menu
 echo ${cls}
 iseq ${osversion} 6.8 && set dir ${menu}/${osversion}/os/${arch} ||