[gnome-system-monitor] remove an unused static member

[Robert Roth <robertroth src gnome org>]

commit f04a66c60b43b194510801f03bebda8aedcec2ef
Author: Elias Aebi <353-eyelash users noreply gitlab gnome org>
Date:   Sat Jan 22 19:47:55 2022 +0100

    remove an unused static member

 src/smooth_refresh.h | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/src/smooth_refresh.h b/src/smooth_refresh.h
index 8dc1f970..7aa18bac 100644
--- a/src/smooth_refresh.h
+++ b/src/smooth_refresh.h
@@ -51,7 +51,6 @@ class SmoothRefresh
 
 
     static const string KEY;
-    static const bool KEY_DEFAULT_VALUE;
 
   private: