usbip: tools usbip_attach: Fix cryptic error messages

Attach device error message is cryptic and useless. Fix it to be
informative.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Reviewed-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>