[SPARK-5286][SQL] SPARK-5286 followup

https://issues.apache.org/jira/browse/SPARK-5286

Author: Yin Huai <yhuai@databricks.com>

Closes #4755 from yhuai/SPARK-5286-throwable and squashes the following commits:

4c0c450 [Yin Huai] Catch Throwable instead of Exception.

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

@@ -63,10 +63,10 @@ case class DropTable(
     } catch {
       // This table's metadata is not in
       case _: org.apache.hadoop.hive.ql.metadata.InvalidTableException =>
-      // Other exceptions can be caused by users providing wrong parameters in OPTIONS
+      // Other Throwables can be caused by users providing wrong parameters in OPTIONS
       // (e.g. invalid paths). We catch it and log a warning message.
-      // Users should be able to drop such kinds of tables regardless if there is an exception.
-      case e: Exception => log.warn(s"${e.getMessage}")
+      // Users should be able to drop such kinds of tables regardless if there is an error.
+      case e: Throwable => log.warn(s"${e.getMessage}")
     }
     hiveContext.invalidateTable(tableName)
     hiveContext.runSqlHive(s"DROP TABLE $ifExistsClause$tableName")