gevent/__init__.py: remove 'socket' import

that was supposed to trigger WSAStartup in the past (libevent times),
but it seems to be no longer necessary

gevent/__init__.py

@@ -32,13 +32,6 @@ __all__ = ['get_hub',
            'reinit']
 
 
-import sys
-if sys.platform == 'win32':
-    import socket  # trigger WSAStartup call
-    del socket
-del sys
-
-
 from gevent.hub import get_hub, iwait, wait
 from gevent.greenlet import Greenlet, joinall, killall
 spawn = Greenlet.spawn