reset namespace columns in migration

.gitlab-ci.yml

@@ -412,7 +412,6 @@ db:migrate:reset-mysql:
 
 .migration-paths: &migration-paths
   <<: *dedicated-runner
-  <<: *only-canonical-masters
   <<: *pull-cache
   stage: test
   variables:

db/migrate/20170825104051_migrate_issues_to_ghost_user.rb

@@ -18,6 +18,7 @@ class MigrateIssuesToGhostUser < ActiveRecord::Migration
     ActiveRecord::Base.clear_cache!
 
     ::User.reset_column_information
+    ::Namespace.reset_column_information
   end
 
   def up