Detect when command in the container exit

Fix #571

gns3server/modules/docker/docker_vm.py

@@ -486,7 +486,9 @@ class DockerVM(BaseVM):
                 out.feed_eof()
                 ws.close()
                 break
+        yield from self.stop()
 
+    @asyncio.coroutine
     def is_running(self):
         """Checks if the container is running.
 
@@ -530,8 +532,8 @@ class DockerVM(BaseVM):
             if state == "paused":
                 yield from self.unpause()
 
+            if state != "stopped":
                 yield from self._fix_permissions()
-
                 # t=5 number of seconds to wait before killing the container
                 try:
                     yield from self.manager.query("POST", "containers/{}/stop".format(self._cid), params={"t": 5})
@@ -544,6 +546,7 @@ class DockerVM(BaseVM):
         except RuntimeError as e:
             log.debug("Docker runtime error when closing: {}".format(str(e)))
             return
+        self.status = "stopped"
 
     @asyncio.coroutine
     def pause(self):