Replace asyncio.async() by asyncio.ensure_future() in tests. Ref #2566.

tests/handlers/api/controller/test_link.py

@@ -356,7 +356,7 @@ def test_pcap(http_controller, tmpdir, project, compute, loop):
     project._links = {link.id: link}
 
     future = asyncio.Future()
-    asyncio.async(go(future))
+    asyncio.ensure_future(go(future))
     response = loop.run_until_complete(future)
     assert response.status == 200
     assert b'hello' == response.body

tests/handlers/api/controller/test_project.py

@@ -179,7 +179,7 @@ def test_notification(http_controller, project, controller, loop, async_run):
         response.close()
         return response
 
-    response = async_run(asyncio.async(go()))
+    response = async_run(asyncio.ensure_future(go()))
     assert response.status == 200
     assert b'"action": "ping"' in response.body
     assert b'"cpu_usage_percent"' in response.body