Revert "[SPARK-8498] [TUNGSTEN] fix npe in errorhandling path in unsafeshuffle writer"

This reverts commit 3348245055.

Reverting because `catch (Exception e) ... throw e` doesn't compile under
Java 6 unless the method declares that it throws Exception.

core/src/main/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleWriter.java

@@ -139,9 +139,6 @@ public class UnsafeShuffleWriter<K, V> extends ShuffleWriter<K, V> {
 
   @Override
   public void write(scala.collection.Iterator<Product2<K, V>> records) throws IOException {
-    // Keep track of success so we know if we ecountered an exception
-    // We do this rather than a standard try/catch/re-throw to handle
-    // generic throwables.
     boolean success = false;
     try {
       while (records.hasNext()) {
@@ -150,19 +147,8 @@ public class UnsafeShuffleWriter<K, V> extends ShuffleWriter<K, V> {
       closeAndWriteOutput();
       success = true;
     } finally {
-      if (sorter != null) {
+      if (!success) {
-        try {
         sorter.cleanupAfterError();
-        } catch (Exception e) {
-          // Only throw this error if we won't be masking another
-          // error.
-          if (success) {
-            throw e;
-          } else {
-            logger.error("In addition to a failure during writing, we failed during " +
-                         "cleanup.", e);
-          }
-        }
       }
     }
   }

core/src/test/java/org/apache/spark/shuffle/unsafe/UnsafeShuffleWriterSuite.java

@@ -253,23 +253,6 @@ public class UnsafeShuffleWriterSuite {
     createWriter(false).stop(false);
   }
 
-  class PandaException extends RuntimeException {
-  }
-
-  @Test(expected=PandaException.class)
-  public void writeFailurePropagates() throws Exception {
-    class BadRecords extends scala.collection.AbstractIterator<Product2<Object, Object>> {
-      @Override public boolean hasNext() {
-        throw new PandaException();
-      }
-      @Override public Product2<Object, Object> next() {
-        return null;
-      }
-    }
-    final UnsafeShuffleWriter<Object, Object> writer = createWriter(true);
-    writer.write(new BadRecords());
-  }
-
   @Test
   public void writeEmptyIterator() throws Exception {
     final UnsafeShuffleWriter<Object, Object> writer = createWriter(true);