CONNECT engine table_type=JDBC non-VARCHAR column types do not return NULL correctly

Non-VARCHAR column types on remote servers that have null values show up with ZERO values rather than null.

For example, in the query results below from a CONNECT table of type JDBC, the second row should contain all NULL values. However, only the first column of type VARCHAR actually returns null, the rest incorrectly return zero values.

varchar  bigint   double    bit    date                time

Tigger    9          75.23      1     2016-10-00    15:00:00

NULL     0            0           0     1970-01-01    00:00:00