Print task is executed asynchronously even if asyncTimeout is not preset

[kdivanov]

Print task is executed asynchronous even if asyncTimeout is not preset. v1.1.0.1414

Steps to reproduce:

1. Turn off the printer
2. Send receipt request without asyncTimeout parameter
3. After ~ 30 seconds taskId is returned instead of error (same thing happens even if you cancel the request after couple of seconds)
4. Turn on the printer
5. Receipt is printed

I expect (not stated in documentation) that it should returns error rather than switching to async mode.

We are not able to decline the payment if the printer is offline. I suppose that dirty fix (still not atomic) would be to check the printer status, but that means that we are gonna double the requests sent to erp.net server.