report initial OR_CONN as the earliest bootstrap phases

We should always make the earliest bootstrap phases be our first connection to any OR, regardless of whether we already have enough directory info to start building circuits.

When starting to boostrap with existing directory info, there might not be a need to make an initial connection to a bridge or fallback directory server to download directory info. This means that the initial OR_CONN to a bridge or guard displays on a progress bar as 80%, when in fact a fairly "early" dependency (the initial connection to any OR) could be failing.

Intuitively, starting Tor Browser and seeing the progress bar hang at 80% for a very long time is frustrating and misleading. A user who sees the progress bar hang at at 5% or 10% has a much better idea of what's going on.

Existing directory info can be reflected in the progress bar as a rapid jump after the initial OR_CONN succeeds. This seems less likely to frustrate users.