run gulp rev before brandable_css in compile_assets

fixes: CNVS-39666

test plan:
* rm -rf public/dist
* bundle exec rake canvas:compile_assets
* load a page, you should see the branding
  for your brand. AKA, the page should not be
  just plain white with no colors.

Change-Id: I794544a1ae6f84df377d8a98ed3c24a6409e20b5
Reviewed-on: https://gerrit.instructure.com/127830
Reviewed-by: Jacob Fugal <jacob@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins
Product-Review: Ryan Shaw <ryan@instructure.com>
QA-Review: Ryan Shaw <ryan@instructure.com>

lib/tasks/canvas.rake

@@ -56,6 +56,8 @@ namespace :canvas do
       }
     end
 
+    raise "Error running gulp rev" unless system('yarn run gulp rev')
+
     if compile_css
       # public/dist/brandable_css/brandable_css_bundles_with_deps.json needs
       # to exist before we run handlebars stuff, so we have to do this first
@@ -108,8 +110,6 @@ namespace :canvas do
     end
     combined_time = times.reduce(:+)
     puts "Finished compiling assets in #{real_time}. parallelism saved #{combined_time - real_time} (#{real_time.to_f / combined_time.to_f * 100.0}%)"
-
-    log_time("gulp rev") { Rake::Task['js:gulp_rev'].invoke }
   end
 
   desc "Just compile css and js for development"

lib/tasks/js.rake

@@ -56,8 +56,4 @@ namespace :js do
     end
   end
 
-  desc "Run Gulp Rev, for fingerprinting assets"
-  task :gulp_rev do
-    raise "Error reving files" unless system('node_modules/.bin/gulp rev')
-  end
 end