optional binary fields throw NPE on default byte[] getters

As it turns out, the fix for https://issues.apache.org/jira/browse/THRIFT-894 in 0.5.0-rc0 is broken wrt optional binary fields, the BufferFor<Field> methods work fine and return a null ByteBuffer, however the get<Field> will NPE, for example a call to the accessor for the unfilled optional binary field ColumnEntry.data causes:

java.lang.NullPointerException
at org.apache.thrift.TBaseHelper.wrapsFullArray(TBaseHelper.java:256)
at org.apache.thrift.TBaseHelper.rightSize(TBaseHelper.java:273)
at com.twitter.service.metastore.gen.ColumnEntry.getData(Unknown Source)