test: retry when write to a socket fails on macOS

If the socket is tearing down macOS will return EPROTOTYPE instead of EPIPE.
Because python doesn't handle this internally we have to do a workaround and retry the request.
See https://bugs.python.org/issue33450

test/functional/test_framework/authproxy.py

@@ -115,6 +115,8 @@ class AuthServiceProxy():
         except OSError as e:
             retry = (
                 '[WinError 10053] An established connection was aborted by the software in your host machine' in str(e))
+            # Workaround for a bug on macOS. See https://bugs.python.org/issue33450
+            retry = retry or ('[Errno 41] Protocol wrong type for socket' in str(e))
             if retry:
                 self.__conn.close()
                 self.__conn.request(method, path, postdata, headers)