(buffer, modify) The storage associated with the buffer
will be deleted. The gss_buffer_desc object will not be freed,
but its length field will be zeroed.
Free storage associated with a buffer. The storage must have been
allocated by a GSS-API routine. In addition to freeing the
associated storage, the routine will zero the length field in the
descriptor to which the buffer parameter refers, and
implementations are encouraged to additionally set the pointer
field in the descriptor to NULL. Any buffer object returned by a
GSS-API routine may be passed to gss_release_buffer (even if there
is no storage associated with the buffer).