LfsServerTest: Remove unnecessary suppression of 'restriction' warning

Change-Id: I23386808848746d201ca1ac13f114c06fc8e86c5
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

org.eclipse.jgit.lfs.server.test/tst/org/eclipse/jgit/lfs/server/fs/LfsServerTest.java

 import org.junit.After;
 import org.junit.Before;
 
-@SuppressWarnings("restriction")
 public abstract class LfsServerTest {
 
 	private static final long timeout = /* 10 sec */ 10 * 1000;