PARQUET-1007: Update parquet.thrift
PARQUET-1007: Update parquet.thrift

Author: Deepak Majeti <deepak.majeti@hpe.com>

Closes #353 from majetideepak/PARQUET-1007 and squashes the following commits:

5bb1d57 [Deepak Majeti] use NA instead of NULL, use parquet.format
155d930 [Deepak Majeti] PARQUET-1007: Update parquet.thrift

apache/parquet-cpp,majetideepak/parquet-cpp,majetideepak/parquet-cpp,advancedxy/parquet-cpp,majetideepak/parquet-cpp,itaiin/parquet-cpp,itaiin/parquet-cpp,advancedxy/parquet-cpp,apache/parquet-cpp,wesm/parquet-cpp,MaxRis/parquet-cpp,apache/parquet-cpp,itaiin/parquet-cpp,advancedxy/parquet-cpp,advancedxy/parquet-cpp,MaxRis/parquet-cpp,MaxRis/parquet-cpp,wesm/parquet-cpp,MaxRis/parquet-cpp,itaiin/parquet-cpp,advancedxy/parquet-cpp,wesm/parquet-cpp,wesm/parquet-cpp,majetideepak/parquet-cpp,apache/parquet-cpp,wesm/parquet-cpp,advancedxy/parquet-cpp,MaxRis/parquet-cpp,itaiin/parquet-cpp,majetideepak/parquet-cpp,MaxRis/parquet-cpp,apache/parquet-cpp,apache/parquet-cpp,itaiin/parquet-cpp,wesm/parquet-cpp,majetideepak/parquet-cpp