[gnome-documents] application: fix fallout from Lang.bind() removal

[Cosimo Cecchi <cosimoc src gnome org>]

commit c6f3fd7c149bf20c30de53b9c71c31659d0deb8b
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Tue Aug 6 12:26:16 2019 +0200

    application: fix fallout from Lang.bind() removal
    
    We lost a variable.

 src/application.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/application.js b/src/application.js
index 7ba88657..eadcd43f 100644
--- a/src/application.js
+++ b/src/application.js
@@ -295,7 +295,7 @@ var Application = GObject.registerClass({
             this._sourceRemovedId = 0;
         }
 
-        this.minersRunning.forEach(() => {
+        this.minersRunning.forEach((miner) => {
             miner._cancellable.cancel();
         });
         this.minersRunning = [];