[gtk+] Adwaita: fix a typo

[Lapo Calamandrei <lapo src gnome org>]

commit 1f3c93583a4fc3db1f8d9d085c7f2214365843c5
Author: Lapo Calamandrei <calamandrei gmail com>
Date:   Tue Mar 8 14:00:01 2016 +0100

    Adwaita: fix a typo

 gtk/theme/Adwaita/_common.scss |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 6a08052..6f35368 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -2020,7 +2020,7 @@ notebook {
  * Scrollbars *
  **************/
 scrollbar {
-  $_slider_min_lenght: 40px;
+  $_slider_min_length: 40px;
 
   // disable steppers
   @at-root * {
@@ -2098,7 +2098,7 @@ scrollbar {
       &.horizontal {
         slider {
           margin: 0 2px;
-          min-width: $_slider_min_lenght;
+          min-width: $_slider_min_length;
         }
 
         button {
@@ -2110,7 +2110,7 @@ scrollbar {
       &.vertical {
         slider {
           margin: 2px 0;
-          min-height: $_slider_min_lenght;
+          min-height: $_slider_min_length;
         }
 
         button {
@@ -2124,9 +2124,9 @@ scrollbar {
     &.hovering { opacity: 0.8; }
   }
 
-  &.horizontal slider { min-width: $_slider_min_lenght; }
+  &.horizontal slider { min-width: $_slider_min_length; }
 
-  &.vertical slider { min-height: $_slider_min_lenght; }
+  &.vertical slider { min-height: $_slider_min_length; }
 
   // button styling
   button {