We should generate v2 mender artifacts for now

mender.xml

@@ -125,7 +125,7 @@
    <arg line="if=${builddir}/disk.img of=${builddir}/${ARTIFACT_NAME}-${BUILD_ID}.ext4 bs=1048576 skip=${ABstart} count=${ABsize}"/>
   </exec>
   <exec executable="${builddir}/mender-artifact" dir="${builddir}" failonerror="true">
-   <arg line="write rootfs-image -t ${DEVICE_TYPE} -n ${ARTIFACT_NAME}-${BUILD_ID} -u ${ARTIFACT_NAME}-${BUILD_ID}.ext4 -o ${ARTIFACT_NAME}-${BUILD_ID}.mender -k ${basedir}/host/private.key -s artifactscripts"/>
+   <arg line="write rootfs-image -v 2 -t ${DEVICE_TYPE} -n ${ARTIFACT_NAME}-${BUILD_ID} -u ${ARTIFACT_NAME}-${BUILD_ID}.ext4 -o ${ARTIFACT_NAME}-${BUILD_ID}.mender -k ${basedir}/host/private.key -s artifactscripts"/>
   </exec>
   <delete file="${builddir}/mender-artifact"/>
   <delete file="${builddir}/${ARTIFACT_NAME}-${BUILD_ID}.ext4"/>