Rename deprecated variables replacements for status colors

brand-something doesn't exist anymore in boostrap. It's now
accessible with theme-color(something).

Author: kennyadsl

backend/app/assets/stylesheets/spree/backend/globals/_deprecation.scss

@@ -11,7 +11,7 @@ $output-solidus-deprecation-warnings: true !default;
   @if $output-solidus-deprecation-warnings == true {
     @if global-variable-exists($variable) {
       @warn "[Solidus] [Deprecation] `$#{$variable}` is deprecated and will be " +
-        "removed in 3.0.0. Please use Bootstraps $#{$replacement} instead";
+        "removed in 3.0.0. Please use Bootstraps #{$replacement} instead";
     }
   }
 }

backend/app/assets/stylesheets/spree/backend/globals/_variables.scss

@@ -62,11 +62,11 @@ $color-tab-active-bg:           $color-white !default;
 $color-tab-active-border:       $color-white !default;
 
 // Basic flash colors
-@include bs-deprecated-variable("color-success", "brand-success");
+@include bs-deprecated-variable("color-success", "theme-color(success)");
 $color-success:                 $color-green !default;
-@include bs-deprecated-variable("color-notice", "brand-warning");
+@include bs-deprecated-variable("color-notice", "theme-color(warning)");
 $color-notice:                  $color-yellow !default;
-@include bs-deprecated-variable("color-error", "brand-danger");
+@include bs-deprecated-variable("color-error", "theme-color(danger)");
 $color-error:                   $color-red !default;
 
 // Breadcrumb custom variable