Merge branch 'fix-migration-timestamp' into 'master'

Update labels migration timestamp to run earlier than the one that removes namespaces to avoid issues

See merge request gitlab-org/gitlab-ce!16907

db/post_migrate/20171207150300_remove_project_labels_group_id_copy.rb

@@ -0,0 +1,21 @@
+# Copy of 20180202111106 - this one should run before 20171207150343 to fix issues related to
+# the removal of groups with labels.
+
+class RemoveProjectLabelsGroupIdCopy < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    # rubocop:disable Migration/UpdateColumnInBatches
+    update_column_in_batches(:labels, :group_id, nil) do |table, query|
+      query.where(table[:type].eq('ProjectLabel').and(table[:group_id].not_eq(nil)))
+    end
+    # rubocop:enable Migration/UpdateColumnInBatches
+  end
+
+  def down
+  end
+end