[Gtk-3.18][Gtk-3.20]Fix info,warning,question and error classes

This makes them available globally. Now gedit searchbar will turn red if the search items are not found!

gtk-3.0/scss/widgets/_infobar.scss

@@ -8,6 +8,7 @@
 @include exports("infobar") {
     GtkInfoBar {
         border: 0;
+    }
 
     $types: (
         info: ($info_fg_color, $info_bg_color),
@@ -21,18 +22,17 @@
         $fg_color: nth($colors, 1);
         $bg_color: nth($colors, 2);
 
-            &.#{$type} {
+        .#{$type} {
             @include linear-gradient($bg_color);
 
             border: 1px solid shade($bg_color, .8);
             color: $fg_color;
 
-                .button {
+            button {
                 @include button($bg_color, $fg_color);
 
                 &.close { @extend %close_button; }
             }
         }
     }
-    }
 }

gtk-3.20/scss/widgets/_infobar.scss

@@ -8,6 +8,7 @@
 @include exports("infobar") {
     infobar {
         border: 0;
+    }
 
     $types: (
         info: ($info_fg_color, $info_bg_color),
@@ -21,7 +22,7 @@
         $fg_color: nth($colors, 1);
         $bg_color: nth($colors, 2);
 
-            &.#{$type} {
+        .#{$type} {
             @include linear-gradient($bg_color);
 
             border: 1px solid shade($bg_color, .8);
@@ -34,5 +35,4 @@
             }
         }
     }
-    }
 }