Change NAME_LEN to CHKSUM_LEN

git-svn-id: svn://irodssvn.ucsd.edu/trunk@5614 ea137bd6-aa86-47b6-b90d-b101d9f19a90
Change NAME_LEN to CHKSUM_LEN. Need Wayne to review the database query related changes.

git-svn-id: svn://irodssvn.ucsd.edu/trunk@5615 ea137bd6-aa86-47b6-b90d-b101d9f19a90