Cleanup duplicated object reuse code in PackWriter

This reuse line was identical between the two branches related to
reusing a delta, or reusing a whole object.  Either way they reuse
the body of the object as-is.  So just make that a common function
after the header is written.

Change-Id: I0e6673b8e813c8c08c594ea2ba546fd366339d5d
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

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

@@ -718,12 +718,11 @@ public class PackWriter {
 		final PackedObjectLoader reuse = open(otp);
 		if (reuse != null) {
 			try {
-				if (otp.isDeltaRepresentation()) {
-					writeDeltaObjectReuse(otp, reuse);
-				} else {
+				if (otp.isDeltaRepresentation())
+					writeDeltaObjectHeader(otp, reuse);
+				else
 					writeObjectHeader(otp.getType(), reuse.getSize());
 				reuse.copyRawData(out, buf, windowCursor);
-				}
 			} finally {
 				reuse.endCopyRawData();
 			}
@@ -773,7 +772,7 @@ public class PackWriter {
 		} while (!deflater.finished());
 	}
 
-	private void writeDeltaObjectReuse(final ObjectToPack otp,
+	private void writeDeltaObjectHeader(final ObjectToPack otp,
 			final PackedObjectLoader reuse) throws IOException {
 		if (deltaBaseAsOffset && otp.getDeltaBase() != null) {
 			writeObjectHeader(Constants.OBJ_OFS_DELTA, reuse.getRawSize());
@@ -792,7 +791,6 @@ public class PackWriter {
 			otp.getDeltaBaseId().copyRawTo(buf, 0);
 			out.write(buf, 0, Constants.OBJECT_ID_LENGTH);
 		}
-		reuse.copyRawData(out, buf, windowCursor);
 	}
 
 	private void writeObjectHeader(final int objectType, long dataLength)