fix python tests failing due to ConnectionRefusedError
fix python tests failing due to ConnectionRefusedError

Summary:
A lot of our python tests occasionally fail due to conn refused error, but for some reason `errno` is not populated, see: https://www.internalfb.com/intern/testinfra/diagnostics/6473924566249005.844424960251435.1658067768/

This causes our retry logic not to kick in in `MCProcess.py`. Here we remove the check for `errno`, just add sufficient amoount of retries as default value.

Reviewed By: stuclar

Differential Revision: D37946972

fbshipit-source-id: 499e99afa257248c394e165e9c17ec3299f731d3

facebook/mcrouter,facebook/mcrouter,facebook/mcrouter,facebook/mcrouter