Change socket.error check from 'is' to '=='
Change socket.error check from 'is' to '=='

Using 'is' for the equality comparison yielded wrong output. 
Even though a 'Connection reset by peer' error was occurring, e was still being raised; instead being handled gracefully by setting data = None.

The behavioural difference between 'is' and '==' in this context shown below.

>>> print(e.errno)
10054
>>> print(errno.ECONNRESET)
10054
>>> type(e.errno)
<class 'int'>
>>> type (errno.ECONNRESET)
<class 'int'>
>>> e.errno is errno.ECONNRESET
False
>>> e.errno == errno.ECONNRESET
True

Hence change 'is' to '==' in the code to handle this error properly.
gragas/simpletcp