uvreq freed too early from isc_nm_connecttimeout_cb()

The isc__nm_uvreq_t is marked as unused too early in the isc__nm_connecttimeout_cb(), the isc__nm_uvreq_put() needs to be called from the original connection callback.

Under normal circumstances, this is not a problem because the isc__nm_uvreq_t is put onto sock->inactivereqs and freed when the isc__nmsocket_t is destroyed.