Fix unclosed resource warnings

Eclipse Kepler thinks these resources are unclosed.

The refactoring in JettyDaemon combines three duplicate invocations
and confuses Kepler's JDT enough that the unclosed resource warning
goes away.

Change-Id: I0f376ac6116082ed645d6712fe5d98add66f493e

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/SshSession.java

@@ -36,6 +36,7 @@ public class SshSession {
     this.account = account;
   }
 
+  @SuppressWarnings("resource")
   public String exec(String command) throws JSchException, IOException {
     ChannelExec channel = (ChannelExec) getSession().openChannel("exec");
     try {