psutil ubuntu 16.04 compatibility

tests/test_wowza.py

@@ -178,7 +178,7 @@ def check_listening() -> tuple:
 
     # get listening ports
     listening = set(
-        c.laddr.port for c in net_connections(kind="inet") if c.status == "LISTEN"
+        c.laddr[1] for c in net_connections(kind="inet") if c.status == "LISTEN"
     )
 
     # check that system is listening on this port