Merge pull request #2047 from edx/fix/btalbot/studio-typographyvariables

Studio - Resolving incorrect Sans Serif Sass Variable Definition

cms/static/sass/_variables.scss

@@ -184,6 +184,6 @@ $lightBluishGrey2: rgb(213, 220, 228);
 $error-red: rgb(253, 87, 87);
 
 // type
-$sans-serif: $f-serif;
+$sans-serif: $f-sans-serif;
 $body-line-height: golden-ratio(.875em, 1);