Type of auto upgrade status.
It depends on h3cHPEOCCltAutoUpgrade status.
flash - The CLT auto upgrade the firmware inside its flash
to the CNUs.
ftp - First download the firmware from FTP server to the CLT,
then the CLT auto upgrade the firmware to the CNUs.
tftp - First download the firmware from TFTP server to the CLT,
then the CLT auto upgrade the firmware to the CNUs.