Modify partitioning in xCAT's images

To modify the partition layout, edit /opt/xcat/share/xcat/install/scripts/pre.rh at line 274:

vi /opt/xcat/share/xcat/install/scripts/pre.rh
echo "part /boot --size 256 --fstype $BOOTFSTYPE --ondisk $instdisk" >> /tmp/partitioning
echo "part swap --recommended --ondisk $instdisk" >> /tmp/partitioning
echo "part / --size 1 --grow --ondisk $instdisk --fstype $FSTYPE" >> /tmp/partitioning