Allow date types with IN operator for partition pruning.

tpch_partition> \d lineitem

table name: tpch_partition.lineitem
table uri: hdfs://localhost:9010/tajo/warehouse/tpch_partition/lineitem
store type: TEXT
number of rows: 0
volume: 696.5 MB
Options: 
	'transient_lastDdlTime'='1441266430'
	'text.null'='\\N'
	'text.delimiter'='|'

schema: 
l_orderkey	INT8
l_partkey	INT8
l_suppkey	INT8
l_linenumber	INT8
l_quantity	FLOAT8
l_extendedprice	FLOAT8
l_discount	FLOAT8
l_tax	FLOAT8
l_returnflag	TEXT
l_linestatus	TEXT
l_commitdate	DATE
l_receiptdate	DATE
l_shipinstruct	TEXT
l_shipmode	TEXT
l_comment	TEXT

Partitions: 
type:COLUMN
columns::tpch_partition.lineitem.l_shipdate (DATE)

tpch_partition> select l_shipdate, count(*) from lineitem where l_shipdate in ( to_date('1992-01-02', 'YYYY-MM-DD') 
>  ,  to_date('1992-02-24', 'YYYY-MM-DD')) group by l_shipdate;
ERROR: internal error: Unsupported type: DATE