Error thrown from runHttpQuery results in "Headers have already sent." warning from moleculer-web

[kthompson23]

When the catch handler in moleculerApollo.js runs as a result of runHttpQuery throwing an error, it sets the status code on the response and calls end. Later in moleculer-web when we hit the sendResponse method, it logs a warning message "Headers have already sent." because response headers were already sent by moleculer-apollo.

This isn't causing any issue other than additional noise in the logs.

Instead of calling res.end in moleculerApollo.js, if the error message and status code was returned it could be passed to service.sendResponse and the error would be handled by moleculer-web.

[icebob]

Could you help about it with a PR?