After reconnecting to the DB, don't present a 404 page
Occasionally, for various reasons, I'll be working on a site where the DB info isn't correct, or the DB is empty, or MySQL is unavailable. Since Craft can't connect to the database (for whatever reason), it will redirect you to `/admin/install`.
So I do the obvious thing and fix my DB credentials. Or load up the SQL file which I accidentally skipped. Or turn on MySQL. In theory, everything should immediately go "back to normal", right?
Not exactly. Remember, when Craft couldn't find the DB, it redirected to `/admin/install`. And now that the DB is reconnected, we're still looking at the `/admin/install` page. So instead of seeing the page I was originally trying to view, we're stuck looking at a 404 "Page not found" error on `/admin/install`.
I know it's a minor complaint, but... Can we have Craft redirect to the previously viewed page (or at least the Dashboard) once Craft realizes that the DB connection is valid, and there's no need to run the installer?