fix M-x filer-at-directory not opening if not already open

fixes #1597

Author: vindarel

src/ext/filer.lisp

@@ -186,8 +186,8 @@
                                          :gravity :cursor
                                          :use-border t)))
     (when (filer-active-p)
-      (deactive-filer)
-    (make-leftside-window (make-filer-buffer directory)))))
+      (deactive-filer))
+    (make-leftside-window (make-filer-buffer directory))))
 
 (define-command filer-select () ()
   (select (back-to-indentation (current-point))))