I2PTunnel: Fix a shared client configured with i2cp.newDestOnResume

not restarting correctly, caused by previous checkin

apps/streaming/java/src/net/i2p/client/streaming/I2PSocketManagerFull.java

@@ -338,6 +338,15 @@ public class I2PSocketManagerFull implements I2PSocketManager {
         }
     }
 
+    /**
+     * Has the socket manager been destroyed?
+     *
+     * @since 0.9.9
+     */
+    public boolean isDestroyed() {
+        return _isDestroyed.get();
+    }
+
     /**
      * Retrieve a set of currently connected I2PSockets, either initiated locally or remotely.
      *