PiggyBank DBStorage DATETIME should use setTimestamp with java.sql.Timestamp

In Pig 0.12.1 PiggyBank DBStorage (contrib/piggybank/java/src/main/java/org/apache/pig/piggybank/storage/DBStorage.java), the code uses the wrong setter and Java data type for the SQL DATETIME datatype.

DATETIME has both date and time, so should use java.sql.Timestamp instead of java.sql.Date (which zeros the time fields).

replace line 121
case DataType.DATETIME:

• ps.setDate(sqlPos, new Date(((DateTime) field).getMillis()));
  sqlPos++;
  break;
  with
  case DataType.DATETIME:
  + ps.setTimestamp(sqlPos, new Timestamp(((DateTime) field).getMillis(
  )));
  sqlPos++;
  break;