- Fix NPE on destroy() if init() failed

apps/i2psnark/java/src/org/klomp/snark/web/I2PSnarkServlet.java

@@ -89,7 +89,8 @@ public class I2PSnarkServlet extends DefaultServlet {
     
     @Override
     public void destroy() {
-        _manager.stop();
+        if (_manager != null)
+            _manager.stop();
         super.destroy();
     }