fix TestIW.testThreadInterruptDeadlock to properly close (abort) its writer

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@980369 13f79535-47bb-0310-9956-ffa450edef68

lucene/src/test/org/apache/lucene/index/TestIndexWriter.java

@@ -4387,6 +4387,12 @@ public class TestIndexWriter extends LuceneTestCase {
         }
       }
 
+      try {
+        w.rollback();
+      } catch (IOException ioe) {
+        throw new RuntimeException(ioe);
+      }
+
       if (!failed) {
         try {
           _TestUtil.checkIndex(dir);