Fix callback validation

Signed-off-by: Adam Hoka <hoka.adam@nexogen.hu>

lib/web/imageRouter/filesystem.js

@@ -2,6 +2,7 @@
 const url = require('url')
 
 const config = require('../../config')
+const logger = require('../../logger')
 
 exports.uploadImage = function (imagePath, callback) {
   if (!imagePath || typeof imagePath !== 'string') {
@@ -10,7 +11,7 @@ exports.uploadImage = function (imagePath, callback) {
   }
 
   if (!callback || typeof callback !== 'function') {
-    callback(new Error('Callback has to be a function'), null)
+    logger.error('Callback has to be a function')
     return
   }