HK-532, set the parent pointer of vars to NULL when transforming DAP4 to DAP2.
HK-532, set the parent pointer of vars to NULL when transforming DAP4 to DAP2.

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