[SPARK-16964][SQL] Remove private[hive] from sql.hive.execution package

## What changes were proposed in this pull request?
This PR is a small follow-up to https://github.com/apache/spark/pull/14554. This also widens the visibility of a few (similar) Hive classes.

## How was this patch tested?
No test. Only a visibility change.

Author: Herman van Hovell <hvanhovell@databricks.com>

Closes #14654 from hvanhovell/SPARK-16964-hive.

sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/CreateHiveTableAsSelectCommand.scala

@@ -34,7 +34,6 @@ import org.apache.spark.sql.hive.MetastoreRelation
  * @param ignoreIfExists allow continue working if it's already exists, otherwise
  *                      raise exception
  */
-private[hive]
 case class CreateHiveTableAsSelectCommand(
     tableDesc: CatalogTable,
     query: LogicalPlan,

sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/ScriptTransformation.scala

@@ -51,7 +51,6 @@ import org.apache.spark.util.{CircularBuffer, RedirectThread, SerializableConfig
  * @param script the command that should be executed.
  * @param output the attributes that are produced by the script.
  */
-private[hive]
 case class ScriptTransformation(
     input: Seq[Expression],
     script: String,
@@ -338,7 +337,6 @@ private class ScriptTransformationWriterThread(
   }
 }
 
-private[hive]
 object HiveScriptIOSchema {
   def apply(input: ScriptInputOutputSchema): HiveScriptIOSchema = {
     HiveScriptIOSchema(
@@ -357,7 +355,6 @@ object HiveScriptIOSchema {
 /**
  * The wrapper class of Hive input and output schema properties
  */
-private[hive]
 case class HiveScriptIOSchema (
     inputRowFormat: Seq[(String, String)],
     outputRowFormat: Seq[(String, String)],

sql/hive/src/main/scala/org/apache/spark/sql/hive/orc/OrcFileFormat.scala

@@ -45,8 +45,7 @@ import org.apache.spark.util.SerializableConfiguration
  * [[FileFormat]] for reading ORC files. If this is moved or renamed, please update
  * [[DataSource]]'s backwardCompatibilityMap.
  */
-private[sql] class OrcFileFormat
-  extends FileFormat with DataSourceRegister with Serializable {
+class OrcFileFormat extends FileFormat with DataSourceRegister with Serializable {
 
   override def shortName(): String = "orc"