[FAB-3201] Fix broken link from css custom file

This change removes references to non-existent image file
from the css file.

Change-Id: Ib4948dc3454fa64be04d551bf42e76d7c7750872
Signed-off-by: Arnaud J Le Hors <[email protected]>

Author: lehors

docs/source/_static/css/custom.css

@@ -52,7 +52,7 @@ a:visited {
 
 .wy-side-nav-search a.icon-home {
     color: transparent;
-    background-image: url('../images/fabric1.png');
+/*    background-image: url('../images/fabric1.png'); */
     background-repeat: no-repeat;
     background-size: Auto 20px;
     background-position: center top;
@@ -173,7 +173,7 @@ a:visited {
 
 .wy-nav-top a {
     color: transparent;
-    background-image: url('../images/fabric1.png');
+/*    background-image: url('../images/fabric1.png'); */
     background-repeat: no-repeat;
     background-size: Auto 19px;
     background-position: center top;