Delete volume when dropping the container

Fix #567

gns3server/modules/docker/docker_vm.py

@@ -583,7 +583,9 @@ class DockerVM(BaseVM):
             state = yield from self._get_container_state()
             if state == "paused" or state == "running":
                 yield from self.stop()
-            yield from self.manager.query("DELETE", "containers/{}".format(self._cid), params={"force": 1})
+            # v – 1/True/true or 0/False/false, Remove the volumes associated to the container. Default false.
+            # force - 1/True/true or 0/False/false, Kill then remove the container. Default false.
+            yield from self.manager.query("DELETE", "containers/{}".format(self._cid), params={"force": 1, "v": 1})
             log.info("Docker container '{name}' [{image}] removed".format(
                 name=self._name, image=self._image))