Remove monkey patching to avoid race conditions

[FloopCZ]

Yielding (probably in minio) during http calls and I/O causes some ugly race conditions in is_job_done and maybe some other places.

[janbuchar]

Could you elaborate on "ugly race conditions", please? I'm not against removing a part of the monkey patching stuff, but I'm afraid that removing it completely would severely harm the responsiveness of the API.

[FloopCZ]

Yes, we can discuss this tomorrow with @blazekadam
as well. For instance, yielding greenlet in between the two checks in this condition can cause UnknownJobError even though the job has just finished processing. But there are probably multiple such issues and I was not able to mark some block as synchronized for gevent.

[janbuchar]

There is a hacky way to do that: call reload(socket) to remove the monkey patches and then monkey.patch() when you're done.

[petrbel]

Produces #29