[SPARK-12742] [SQL] org.apache.spark.sql.hive.LogicalPlanToSQLSuite failure due to Table already exists exception

[scwf]

[info] Exception encountered when attempting to run a suite with class name: 
org.apache.spark.sql.hive.LogicalPlanToSQLSuite *** ABORTED *** (325 milliseconds)
[info]   org.apache.spark.sql.AnalysisException: Table `t1` already exists.;
[info]   at org.apache.spark.sql.DataFrameWriter.saveAsTable(DataFrameWriter.scala:296)
[info]   at org.apache.spark.sql.DataFrameWriter.saveAsTable(DataFrameWriter.scala:285)
[info]   at org.apache.spark.sql.hive.LogicalPlanToSQLSuite.beforeAll(LogicalPlanToSQLSuite.scala:33)
[info]   at org.scalatest.BeforeAndAfterAll$class.beforeAll(BeforeAndAfterAll.scala:187)
[info]   at org.apache.spark.sql.hive.LogicalPlanToSQLSuite.beforeAll(LogicalPlanToSQLSuite.scala:23)
[info]   at org.scalatest.BeforeAndAfterAll$class.run(BeforeAndAfterAll.scala:253)
[info]   at org.apache.spark.sql.hive.LogicalPlanToSQLSuite.run(LogicalPlanToSQLSuite.scala:23)
[info]   at org.scalatest.tools.Framework.org$scalatest$tools$Framework$$runSuite(Framework.scala:462)
[info]   at org.scalatest.tools.Framework$ScalaTestTask.execute(Framework.scala:671)
[info]   at sbt.ForkMain$Run$2.call(ForkMain.java:296)
[info]   at sbt.ForkMain$Run$2.call(ForkMain.java:286)
[info]   at java.util.concurrent.FutureTask.run(FutureTask.java:266)
[info]   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
[info]   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
[info]   at java.lang.Thread.run(Thread.java:745)

/cc @liancheng

[SparkQA]

Test build #49059 has finished for PR 10682 at commit 62dd2f4.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[scwf]

@liancheng t1 table must be created in other test suite, so here i just drop them before run this suite.

[liancheng]

@scwf LGTM, merging to master. Thanks for fixing this!