Use chunked encoding when uploading LFS objects

to avoid OOM when transferring very large objects. Use a chunk size
of 256kB. In jgit-186 a user reported that uploading objects larger
than 2GB fails with an OOM error.

Bug: jgit-186
Change-Id: I6876f3cbb60b3a08d6d1ff3d6bcd8ac6ee8cd442

org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPrePushHook.java

diff --git a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPrePushHook.java b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPrePushHook.java
index 9b3d608..802835c 100644
--- a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPrePushHook.java
+++ b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPrePushHook.java
@@ -246,6 +246,7 @@ private void uploadFile(Protocol.ObjectInfo o,
 				.getLfsContentConnection(getRepository(), uploadAction,
 						METHOD_PUT);
 		contentServer.setDoOutput(true);
+		contentServer.setChunkedStreamingMode(256 << 10);
 		try (OutputStream out = contentServer
 				.getOutputStream()) {
 			long size = Files.copy(path, out);