socket: Free poll handle when resetting socket state

Since 07cb0be12 we are not closing the user provided FDs,
but the above change also resulted in memory leak during
ssh_disconnect that left the poll_handle allocated during
reset.

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

src/socket.c

@@ -202,7 +202,10 @@ void ssh_socket_reset(ssh_socket s)
     s->read_wontblock = 0;
     s->write_wontblock = 0;
     s->data_except = 0;
-    s->poll_handle = NULL;
+    if (s->poll_handle != NULL) {
+        ssh_poll_free(s->poll_handle);
+        s->poll_handle = NULL;
+    }
     s->state=SSH_SOCKET_NONE;
 #ifndef _WIN32
     s->proxy_pid = 0;