Bug 1381860 - Fix reference to external server for font in test, r=annevk

MozReview-Commit-ID: GD7SH2HedRa

testing/web-platform/tests/css/css-variables-1/vars-font-shorthand-001.html

@@ -8,7 +8,7 @@
 
 @font-face {
 	font-family: Ahem;
-	src: url(https://cdn.rawgit.com/w3c/csswg-test/master/fonts/ahem/ahem.ttf);
+	src: url(/css/fonts/ahem/ahem.ttf);
 }
 
 div {