Correclty cleanup packet capture objects when closing server

Fix #592

gns3server/controller/compute.py

@@ -295,11 +295,24 @@ class Compute:
         :returns: A file stream
         """
 
+        # Due to Python 3.4 limitation we can't use with and asyncio
+        # https://www.python.org/dev/peps/pep-0492/
+        # that why we wrap the answer
+        class StreamResponse:
+            def __init__(self, response):
+                self._response = response
+
+            def __enter__(self):
+                return self._response.content
+
+            def __exit__(self):
+                self._response.close()
+
         url = self._getUrl("/projects/{}/stream/{}".format(project.id, path))
         response = yield from self._session().request("GET", url, auth=self._auth)
         if response.status == 404:
             raise aiohttp.web.HTTPNotFound(text="{} not found on compute".format(path))
-        return response.content
+        return StreamResponse(response)
 
     @asyncio.coroutine
     def http_query(self, method, path, data=None, **kwargs):