Changed comparison in set_max_size() so that it uses ULONG_MAX (since  the method uses a long) and does not test for negative sizes (since size is unsigned).
Changed comparison in set_max_size() so that it uses ULONG_MAX (since 
the method uses a long) and does not test for negative sizes (since size
is unsigned).

OPENDAP/libdap4,OPENDAP/libdap4,OPENDAP/libdap4,OPENDAP/libdap,OPENDAP/libdap4,OPENDAP/libdap,OPENDAP/libdap4,OPENDAP/libdap,OPENDAP/libdap,OPENDAP/libdap4