[SPARK-6611][SQL] Add support for INTEGER as synonym of INT.

https://issues.apache.org/jira/browse/SPARK-6611

Author: Santiago M. Mola <santiago.mola@sap.com>

Closes #5271 from smola/features/integer-parse and squashes the following commits:

f5c1c64 [Santiago M. Mola] [SPARK-6611] Add support for INTEGER as synonym of INT.

sql/catalyst/src/main/scala/org/apache/spark/sql/types/DataTypeParser.scala

@@ -40,7 +40,7 @@ private[sql] trait DataTypeParser extends StandardTokenParsers {
   protected lazy val primitiveType: Parser[DataType] =
     "(?i)string".r ^^^ StringType |
     "(?i)float".r ^^^ FloatType |
-    "(?i)int".r ^^^ IntegerType |
+    "(?i)(?:int|integer)".r ^^^ IntegerType |
     "(?i)tinyint".r ^^^ ByteType |
     "(?i)smallint".r ^^^ ShortType |
     "(?i)double".r ^^^ DoubleType |

sql/catalyst/src/test/scala/org/apache/spark/sql/types/DataTypeParserSuite.scala

@@ -34,10 +34,12 @@ class DataTypeParserSuite extends FunSuite {
   }
 
   checkDataType("int", IntegerType)
+  checkDataType("integer", IntegerType)
   checkDataType("BooLean", BooleanType)
   checkDataType("tinYint", ByteType)
   checkDataType("smallINT", ShortType)
   checkDataType("INT", IntegerType)
+  checkDataType("INTEGER", IntegerType)
   checkDataType("bigint", LongType)
   checkDataType("float", FloatType)
   checkDataType("dOUBle", DoubleType)