Previously, or_connection_t did not record whether or not the
connection uses a pluggable transport. Instead, it stored the
underlying proxy protocol of the pluggable transport in
proxy_type. This made bootstrap reporting treat pluggable transport
connections as plain proxy connections.
Store a separate bit indicating whether a pluggable transport is in
use, and decode this during bootstrap reporting.
Fixes bug 28925; bugfix on 0.4.0.1-alpha.
