Add a redirect for the virus scanning page that Google has indexed
Add a redirect for the virus scanning page that Google has indexed

- Google has indexed the old URL (`manual/virus-scanning.html`) and so
  it 404s. Redirect to what appears to be the actual page.

alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs