Make PreP partition the first partition for ppc64le

The PreP partition needs to be the first partition for installation on most ppc systems
including powerVM which IBM is testing openshift installations on.

src/create_disk.sh

@@ -127,14 +127,15 @@ case "$arch" in
         sgdisk -p "$disk"
         ;;
     ppc64le)
+        BOOTPN=2
+        PREPPN=1
         # ppc64le doesn't use special uuid for root partition
         sgdisk -Z $disk \
         -U 00000000-0000-4000-a000-000000000001 \
-        -n 2:0:+4M   -c 2:PowerPC-PReP-boot -t 2:9E1A2D38-C612-4316-AA26-8B49521E5A8B \
+        -n ${PREPPN}:0:+4M   -c ${PREPPN}:PowerPC-PReP-boot -t ${PREPPN}:9E1A2D38-C612-4316-AA26-8B49521E5A8B \
         -n ${BOOTPN}:0:+384M -c ${BOOTPN}:boot \
         -n ${ROOTPN}:0:${rootfs_size}     -c ${ROOTPN}:root              -t ${ROOTPN}:0FC63DAF-8483-4772-8E79-3D69D8477DE4
         sgdisk -p "$disk"
-        PREPPN=2
         ;;
 esac