Make SimpleSocket great with python2 again

[fabianfreyer]

2019-04-12 01:07:54,123 - PieChecker - DEBUG - Initialized checker with {"flag_idx": 0, "address": "127.0.0.1", "round": 1, "flag": "ENOFLAGENOFLAG=", "timeout": 30, "team": "foo", "method": "putflag"}
2019-04-12 01:07:54,126 - PieChecker - DEBUG - Opening socket to 127.0.0.1:2323 (timeout 30 secs).
Exception AttributeError: "SimpleSocket instance has no attribute 'sock'" in <bound method SimpleSocket.__del__ of <enochecker.utils.SimpleSocket instance at 0x749585e12f38>> ignored
Traceback (most recent call last):
  File "checker.py", line 49, in <module>
    run(PieChecker)
  File "/home/user/.local/lib/python2.7/site-packages/enochecker/enochecker.py", line 546, in run
    result = checker_cls(**vars(parsed)).run()
  File "/home/user/.local/lib/python2.7/site-packages/enochecker/enochecker.py", line 267, in run
    ConnectionError,
NameError: global name 'ConnectionError' is not defined

[domenukk]

The commit bc595e8 broke python2 compatibility due to SimpleSocket changes.

[MMunier]

Since Python2 has been dropped this issue is no longer pursued