com.docker.slirp.exe: on failure, close the socket
com.docker.slirp.exe: on failure, close the socket

The recent change to avoid completely failing when the connect failed
neglected to close the socket. This results in a slow leak of sockets
(and 2 threads per socket) while the VM is offline.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@docker.com>

djs55/vpnkit,djs55/vpnkit,djs55/vpnkit,samoht/vpnkit