IndexDiff: Remove always true not-subtree check

The TreeWalk is configured to be recursive, which means subtrees are
never presented to the application.  Therefore the working tree file
mode can never be a subtree/subdirectory at this point in the code.

Change-Id: Ie842ddc147957d09205c0d2ce87b25c566862fd9
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java

@@ -191,7 +191,6 @@ public class IndexDiff {
 					DirCacheIterator.class);
 			WorkingTreeIterator workingTreeIterator = treeWalk.getTree(WORKDIR,
 					WorkingTreeIterator.class);
-			FileMode fileModeTree = treeWalk.getFileMode(TREE);
 
 			if (dirCacheIterator != null) {
 				if (dirCacheIterator.getDirCacheEntry().isAssumeValid())
@@ -208,13 +207,11 @@ public class IndexDiff {
 					}
 				} else {
 					// in repo, not in index => removed
-					if (!fileModeTree.equals(FileMode.TYPE_TREE)) {
 					removed.add(treeWalk.getPathString());
 					changesExist = true;
 					if (workingTreeIterator != null)
 						untracked.add(treeWalk.getPathString());
 				}
-				}
 			} else {
 				if (dirCacheIterator != null) {
 					// not in repo, in index => added