CALSTIS Release Notes v. 2.35

PR 68052:  Calstis failure when an imset is missing (exptime was 0).

When checking whether an image set exists or not, calstis opens the
SCI,EXTVER extension using c_tbtopn, a table I/O function.  If this fails,
c_tbtclo was called to close the extension (usually an image), and -1 was
returned as a flag.  The call to c_tbtclo failed because the file handle
was not assigned a value; it is also unnecessary to call c_tbtclo because
memory had already been freed.  This call to c_tbtclo has been deleted.