Currently Derby requires RDBNAM on ACCSEC. The DDM spec lists it as optional. For
DERBY-728, in order to negotiate the encoding, EXCSAT and ACCSEC will need to remain EBCDIC, so we want the RDBNAM to be optional. We can use the RDBNAM sent in SECCHK instead.
Once this is done. Client can be changed to only send RDBNAM on ACCSEC if an EBCDIC conversion is possible.