fix work with socket on windows

[vmarunov]

fix connection error on windows platform:

>>> import tarantool
>>> tarantool.connect('48.12.22.123',3311)

Traceback (most recent call last):
  File "<pyshell#2>", line 1, in <module>
    tarantool.connect('48.12.22.123',3311)
  File "C:\Python27\lib\site-packages\tarantool\__init__.py", line 47, in connect
    encoding=encoding)
  File "C:\Python27\lib\site-packages\tarantool\connection.py", line 93, in __init__
    recv = self._sys_recv = libc.recv
  File "C:\Python27\lib\ctypes\__init__.py", line 378, in __getattr__
    func = self.__getitem__(name)
  File "C:\Python27\lib\ctypes\__init__.py", line 383, in __getitem__
    func = self._FuncPtr((name_or_ordinal, self))
AttributeError: function 'recv' not found