Use auto-closeable RevWalk when creating review notes

In CreateReviewNotes.createNotes a RevWalk is created, but does not get
closed if an exception occurs when parsing the commit or marking objects
as uninteresting because the method just returns in the catch block. The
RevWalk is only closed in the later finally block that is not reached in
this case.

Enclose both blocks in a try-with-resources for the RevWalk, to ensure
that it always gets closed.

Change-Id: Ief04c620ffe664dd9df5527473fc1a5e6354aa33

src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
index 853585d..72c9ec9 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/reviewnotes/CreateReviewNotes.java
@@ -129,25 +129,24 @@
       return;
     }
 
-    RevWalk rw = new RevWalk(git);
-    try {
-      RevCommit n = rw.parseCommit(newObjectId);
-      rw.markStart(n);
-      if (n.getParentCount() == 1 && n.getParent(0).equals(oldObjectId)) {
-        rw.markUninteresting(rw.parseCommit(oldObjectId));
-      } else {
-        markUninteresting(git, branch, rw, oldObjectId);
+    try (RevWalk rw = new RevWalk(git)) {
+      try {
+        RevCommit n = rw.parseCommit(newObjectId);
+        rw.markStart(n);
+        if (n.getParentCount() == 1 && n.getParent(0).equals(oldObjectId)) {
+          rw.markUninteresting(rw.parseCommit(oldObjectId));
+        } else {
+          markUninteresting(git, branch, rw, oldObjectId);
+        }
+      } catch (Exception e) {
+        log.error(e.getMessage(), e);
+        return;
       }
-    } catch (Exception e) {
-      log.error(e.getMessage(), e);
-      return;
-    }
 
-    if (monitor == null) {
-      monitor = NullProgressMonitor.INSTANCE;
-    }
+      if (monitor == null) {
+        monitor = NullProgressMonitor.INSTANCE;
+      }
 
-    try {
       for (RevCommit c : rw) {
         ObjectId content = createNoteContent(loadPatchSet(c, branch));
         if (content != null) {
@@ -156,8 +155,6 @@
           getMessage().append("* ").append(c.getShortMessage()).append("\n");
         }
       }
-    } finally {
-      rw.close();
     }
   }