Handle properly issue when write happens to closed session

[Gormartsen]

When callback called second time and respond already sent.

Error: write after end
    at write_ (_http_outgoing.js:625:15)
    at ServerResponse.write (_http_outgoing.js:620:10)
    at WebServer.callbackExecutor (xxxxxxx/node_modules/@microservice-framework/microservice-cluster/includes/web.js:204:14)
    at WebServer.callbackExecutor (xxxxxxx/node_modules/@microservice-framework/microservice-cluster/includes/web.js:10:63)
    at xxxxxxx/node_modules/@microservice-framework/microservice-cluster/includes/web.js:173:14