Use integer depth in PackWriter's DepthAwareVisitationPolicy

- ObjectWalk.getTreeDepth() returns int hence there is no need to use
long depths in the lowestDepthVisited map.
- Also fix boxing warnings introduced in 0a15cb3a.

Change-Id: I6d73b6f41d5d20975d02f376c8588e411eaff0ec
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/pack/PackWriter.java

@@ -881,7 +881,7 @@ public class PackWriter implements AutoCloseable {
 	 */
 	private class DepthAwareVisitationPolicy
 			implements ObjectWalk.VisitationPolicy {
-		private final Map<ObjectId, Long> lowestDepthVisited = new HashMap<>();
+		private final Map<ObjectId, Integer> lowestDepthVisited = new HashMap<>();
 
 		private final ObjectWalk walk;
 
@@ -891,16 +891,16 @@ public class PackWriter implements AutoCloseable {
 
 		@Override
 		public boolean shouldVisit(RevObject o) {
-			Long lastDepth = lowestDepthVisited.get(o);
+			Integer lastDepth = lowestDepthVisited.get(o);
 			if (lastDepth == null) {
 				return true;
 			}
-			return walk.getTreeDepth() < lastDepth;
+			return walk.getTreeDepth() < lastDepth.intValue();
 		}
 
 		@Override
 		public void visited(RevObject o) {
-			lowestDepthVisited.put(o, (long) walk.getTreeDepth());
+			lowestDepthVisited.put(o, Integer.valueOf(walk.getTreeDepth()));
 		}
 	}