[SQL] Use hive.SessionState, not the thread local SessionState

Note that this is simply mimicing lookupRelation(). I do not have a conrete
notion of why this solution is necessarily right-er than SessionState.get,
but SessionState.get is returning null.

Author: aarondav

sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveMetastoreCatalog.scala

@@ -105,7 +105,7 @@ private[hive] class HiveMetastoreCatalog(hive: HiveContext) extends Catalog with
   object CreateTables extends Rule[LogicalPlan] {
     def apply(plan: LogicalPlan): LogicalPlan = plan transform {
       case InsertIntoCreatedTable(db, tableName, child) =>
-        val databaseName = db.getOrElse(SessionState.get.getCurrentDatabase)
+        val databaseName = db.getOrElse(hive.sessionState.getCurrentDatabase)
 
         createTable(databaseName, tableName, child.output)