UploadPack: Rewrite setAdvertiseRefsHook to use ternary operator

This makes the implementation consistent with the other similar
methods in this class.

Change-Id: I007876aad883615d696c8eabc886818ae00b10ee
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

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

@@ -573,10 +573,8 @@ public class UploadPack {
 	 */
 	public void setAdvertiseRefsHook(
 			@Nullable AdvertiseRefsHook advertiseRefsHook) {
-		if (advertiseRefsHook != null)
+		this.advertiseRefsHook = advertiseRefsHook != null ? advertiseRefsHook
-			this.advertiseRefsHook = advertiseRefsHook;
+				: AdvertiseRefsHook.DEFAULT;
-		else
-			this.advertiseRefsHook = AdvertiseRefsHook.DEFAULT;
 	}
 
 	/**