Update osa4b.md

The line is not in the example repo and is not referenced in the material. Also the particular file does not have import for http. In my understanding the http package is not used in favor of the express

Author: lxhelmer

src/content/4/fi/osa4b.md

@@ -200,7 +200,7 @@ const app = require('./app') // varsinainen Express-sovellus
 const config = require('./utils/config')
 const logger = require('./utils/logger')
 
-const server = http.createServer(app)
+
 
 app.listen(config.PORT, () => {
   logger.info(`Server running on port ${config.PORT}`)