Revert SPARK-6910 and SPARK-9027

Revert #7216 and #7386.  These patch seems to be causing quite a few test failures:

```
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.GeneratedMethodAccessor322.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.sql.hive.client.Shim_v0_13.getPartitionsByFilter(HiveShim.scala:351)
	at org.apache.spark.sql.hive.client.ClientWrapper$$anonfun$getPartitionsByFilter$1.apply(ClientWrapper.scala:320)
	at org.apache.spark.sql.hive.client.ClientWrapper$$anonfun$getPartitionsByFilter$1.apply(ClientWrapper.scala:318)
	at org.apache.spark.sql.hive.client.ClientWrapper$$anonfun$withHiveState$1.apply(ClientWrapper.scala:180)
	at org.apache.spark.sql.hive.client.ClientWrapper.retryLocked(ClientWrapper.scala:135)
	at org.apache.spark.sql.hive.client.ClientWrapper.withHiveState(ClientWrapper.scala:172)
	at org.apache.spark.sql.hive.client.ClientWrapper.getPartitionsByFilter(ClientWrapper.scala:318)
	at org.apache.spark.sql.hive.client.HiveTable.getPartitions(ClientInterface.scala:78)
	at org.apache.spark.sql.hive.MetastoreRelation.getHiveQlPartitions(HiveMetastoreCatalog.scala:670)
	at org.apache.spark.sql.hive.execution.HiveTableScan.doExecute(HiveTableScan.scala:137)
	at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$1.apply(SparkPlan.scala:90)
	at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$1.apply(SparkPlan.scala:90)
	at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:147)
	at org.apache.spark.sql.execution.SparkPlan.execute(SparkPlan.scala:89)
	at org.apache.spark.sql.execution.Exchange$$anonfun$doExecute$1.apply(Exchange.scala:164)
	at org.apache.spark.sql.execution.Exchange$$anonfun$doExecute$1.apply(Exchange.scala:151)
	at org.apache.spark.sql.catalyst.errors.package$.attachTree(package.scala:48)
	... 85 more
Caused by: MetaException(message:Filtering is supported only on partition keys of type string)
	at org.apache.hadoop.hive.metastore.parser.ExpressionTree$FilterBuilder.setError(ExpressionTree.java:185)
	at org.apache.hadoop.hive.metastore.parser.ExpressionTree$LeafNode.getJdoFilterPushdownParam(ExpressionTree.java:452)
	at org.apache.hadoop.hive.metastore.parser.ExpressionTree$LeafNode.generateJDOFilterOverPartitions(ExpressionTree.java:357)
	at org.apache.hadoop.hive.metastore.parser.ExpressionTree$LeafNode.generateJDOFilter(ExpressionTree.java:279)
	at org.apache.hadoop.hive.metastore.parser.ExpressionTree$TreeNode.generateJDOFilter(ExpressionTree.java:243)
	at org.apache.hadoop.hive.metastore.parser.ExpressionTree.generateJDOFilterFragment(ExpressionTree.java:590)
	at org.apache.hadoop.hive.metastore.ObjectStore.makeQueryFilterString(ObjectStore.java:2417)
	at org.apache.hadoop.hive.metastore.ObjectStore.getPartitionsViaOrmFilter(ObjectStore.java:2029)
	at org.apache.hadoop.hive.metastore.ObjectStore.access$500(ObjectStore.java:146)
	at org.apache.hadoop.hive.metastore.ObjectStore$4.getJdoResult(ObjectStore.java:2332)
```
https://amplab.cs.berkeley.edu/jenkins/view/Spark-QA-Test/job/Spark-Master-Maven-with-YARN/2945/HADOOP_PROFILE=hadoop-2.4,label=centos/testReport/junit/org.apache.spark.sql.hive.execution/SortMergeCompatibilitySuite/auto_sortmerge_join_16/

Author: Michael Armbrust <michael@databricks.com>

Closes #7409 from marmbrus/revertMetastorePushdown and squashes the following commits:

92fabd3 [Michael Armbrust] Revert SPARK-6910 and SPARK-9027
5d3bdf2 [Michael Armbrust] Revert "[SPARK-9027] [SQL] Generalize metastore predicate pushdown"