[SPARK-5741][SQL] Support the path contains comma in HiveContext

When run ```select * from nzhang_part where hr = 'file,';```, it throws exception ```java.lang.IllegalArgumentException: Can not create a Path from an empty string```
. Because the path of hdfs contains comma, and FileInputFormat.setInputPaths will split path by comma.

### SQL
```
set hive.merge.mapfiles=true;
set hive.merge.mapredfiles=true;
set hive.input.format=org.apache.hadoop.hive.ql.io.HiveInputFormat;
set hive.exec.dynamic.partition=true;
set hive.exec.dynamic.partition.mode=nonstrict;

create table nzhang_part like srcpart;

insert overwrite table nzhang_part partition (ds='2010-08-15', hr) select key, value, hr from srcpart where ds='2008-04-08';

insert overwrite table nzhang_part partition (ds='2010-08-15', hr=11) select key, value from srcpart where ds='2008-04-08';

insert overwrite table nzhang_part partition (ds='2010-08-15', hr)
select * from (
select key, value, hr from srcpart where ds='2008-04-08'
union all
select '1' as key, '1' as value, 'file,' as hr from src limit 1) s;

select * from nzhang_part where hr = 'file,';
```

### Error Log
```
15/02/10 14:33:16 ERROR SparkSQLDriver: Failed in [select * from nzhang_part where hr = 'file,']
java.lang.IllegalArgumentException: Can not create a Path from an empty string
at org.apache.hadoop.fs.Path.checkPathArg(Path.java:127)
at org.apache.hadoop.fs.Path.<init>(Path.java:135)
at org.apache.hadoop.util.StringUtils.stringToPath(StringUtils.java:241)
at org.apache.hadoop.mapred.FileInputFormat.setInputPaths(FileInputFormat.java:400)
at org.apache.spark.sql.hive.HadoopTableReader$.initializeLocalJobConfFunc(TableReader.scala:251)
at org.apache.spark.sql.hive.HadoopTableReader$$anonfun$11.apply(TableReader.scala:229)
at org.apache.spark.sql.hive.HadoopTableReader$$anonfun$11.apply(TableReader.scala:229)
at org.apache.spark.rdd.HadoopRDD$$anonfun$getJobConf$6.apply(HadoopRDD.scala:172)
at org.apache.spark.rdd.HadoopRDD$$anonfun$getJobConf$6.apply(HadoopRDD.scala:172)
at scala.Option.map(Option.scala:145)
at org.apache.spark.rdd.HadoopRDD.getJobConf(HadoopRDD.scala:172)
at org.apache.spark.rdd.HadoopRDD.getPartitions(HadoopRDD.scala:196)

Author: q00251598 <qiyadong@huawei.com>

Closes #4532 from watermen/SPARK-5741 and squashes the following commits:

9758ab1 [q00251598] fix bug
1db1a1c [q00251598] use setInputPaths(Job job, Path... inputPaths)
b788a72 [q00251598] change FileInputFormat.setInputPaths to jobConf.set and add test suite

1 files changed, 1 insertions, 0 deletions

diff --git a/sql/hive/compatibility/src/test/scala/org/apache/spark/sql/hive/execution/HiveCompatibilitySuite.scala b/sql/hive/compatibility/src/test/scala/org/apache/spark/sql/hive/execution/HiveCompatibilitySuite.scala
index c6ead4562d..6126ce7130 100644
--- a/sql/hive/compatibility/src/test/scala/org/apache/spark/sql/hive/execution/HiveCompatibilitySuite.scala
+++ b/sql/hive/compatibility/src/test/scala/org/apache/spark/sql/hive/execution/HiveCompatibilitySuite.scala
@@ -632,6 +632,7 @@ class HiveCompatibilitySuite extends HiveQueryFileTest with BeforeAndAfter {
     "mapreduce8",
     "merge1",
     "merge2",
+    "merge4",
     "mergejoins",
     "multiMapJoin1",
     "multiMapJoin2",