Changed hardcoded error values to standard errno system symbols in DaphneTestingInstance

tests/http_base.py

@@ -6,6 +6,7 @@ import time
 import unittest
 from http.client import HTTPConnection
 from urllib import parse
+import errno
 
 from daphne.test_application import TestApplication
 
@@ -31,7 +32,7 @@ class DaphneTestingInstance:
         try:
             s.bind(("127.0.0.1", port))
         except socket.error as e:
-            if e.errno in [13, 98]:
+            if e.errno in [errno.EACCES, errno.EADDRINUSE]:
                 return True
             else:
                 raise