enhance error log

lib/tasks/gather.js

@@ -264,7 +264,7 @@ class TaskGather extends Task {
         .catch((err) => this.logger.info(err, 'Error setting channel variables'));
 
     } catch (err) {
-      this.logger.error("could not init speech for listening");
+      this.logger.error({message: err.message, stack: err.stack}, "could not init speech for listening");
     }
   }