Fix 2 unclosed sockets that can happen on errors in
supervisor/datatypes.py

Fixes 2 of the `ResourceWarning` warnings in GH-391.
Merge pull request #395 from msabramo/feature.py3.fix_two_unclosed_sockets_on_errors

[feature.py3] Fix 2 unclosed sockets that can happen on errors in supervisor/datatypes.py