Change the net test, test_reconnects, to skip itself

Change the net test, test_reconnects, to skip itself as it uses
a test_server_fixture_blocking that calls a SIGUSR1.  Windows can't
SIGUSR1, see: http://docs.python.org/2/library/signal.html#signal.signal
We'll need a Windows specific way of emulating the SIGUSR1 functionality
in the Agent.