Fix for two hive scan issues

1) Hive string columns can be wider in their DDL defnition than their target
   column when inserting from hive. With the fix the output of hive scan will
   be the narrower target column rather than the original wider hive source
   column.
2) option to ignore conversion error during hive/hdfs scan and continue to
   next one. The cqd HDFS_READ_CONTINUE_ON_ERROR should be set to ON to enable
   this option.

Change-Id: Id8afe497e6c043c4b7bae6d556cee76c42ab0163