In the case the SQL node is in a flow with http in and out, the flow end
in case of error but the http client is waiting for an answer. So we
must not endded the flow but send back the error.
We must not store passwords in the regular flows file as this gets exchanged with the browser regularly and would leave things vulnerable.
The credentials mechanism is there to all a write-once-don't-need-to-read approach that allows the runtime access to the credentials without exposing them to the browser.
