fix abstracttable GetSchema is hidden by derived class
fix abstracttable GetSchema is hidden by derived class


Former-commit-id: 65228a915b77fc15d9496e9e32bfd1e0ee258973
larryxiao/peloton-1,larryxiao/peloton,larryxiao/peloton,amaliujia/CMUDB-peloton,ranxian/peloton,larryxiao/peloton,ranxian/peloton,larryxiao/peloton-1,omegaga/peloton,amaliujia/CMUDB-peloton,larryxiao/peloton,omegaga/peloton,larryxiao/peloton-1,larryxiao/peloton-1,omegaga/peloton,amaliujia/CMUDB-peloton,amaliujia/CMUDB-peloton,omegaga/peloton,larryxiao/peloton-1,ranxian/peloton,ranxian/peloton,larryxiao/peloton-1,ranxian/peloton,larryxiao/peloton,amaliujia/CMUDB-peloton,ranxian/peloton,amaliujia/CMUDB-peloton,larryxiao/peloton-1,omegaga/peloton,larryxiao/peloton,omegaga/peloton,amaliujia/CMUDB-peloton,larryxiao/peloton,omegaga/peloton