BUG/MINOR: connection: See new connection as available only on reuse always

When the multiplexer creation is delayed after the handshakes phase, the
connection is added in the available connection list if http-reuse never is not
configured for the backend. But it is a wrong statement. At this step, the
connection is not safe because it is a new connection. So it must be added in
the available connection list only if http-reuse always is used.

No backport needed, this is 2.2-dev.
1 file changed