UploadPack: suppress resource warning for DepthWalk.RevWalk

which borrows the ObjectReader from `walk` which is closed by
UploadPack#close.

Change-Id: Idb91f025c2872421702034381bb55d292d0e74ed

Author: msohn

org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java

@@ -2369,7 +2369,8 @@ else if (ref.getName().startsWith(Constants.R_HEADS))
 						: req.getDepth() - 1;
 				pw.setShallowPack(req.getDepth(), unshallowCommits);
 
-				// Ownership is transferred below
+				// dw borrows the reader from walk which is closed by #close
+				@SuppressWarnings("resource")
 				DepthWalk.RevWalk dw = new DepthWalk.RevWalk(
 						walk.getObjectReader(), walkDepth);
 				dw.setDeepenSince(req.getDeepenSince());