Show correct port and address in connection exception messages

[kmcphillips]

Problem

When rescuing and reraising Errno::ECONNREFUSED and Errno::EHOSTDOWN errors, the error message shows the incorrect port number as always being port 80 when no proxy is used. Meaning the error will always look like Net::HTTP::Persistent::Error: connection refused: 127.0.0.1:80 regardless of the actual port number that was attempted to connect to.

The cause of this comes from Net::HTTP. In net/http when no proxy is passed in, the initialization branch has this line which will always set the proxy port to a default value of 80:
https://github.com/ruby/ruby/blob/ad4f973ecd0a3481ff1abaa972d457e9f5b5fb4e/lib/net/http.rb#L1083

Meaning that when a new http object is initialized without a proxy and is passed (address, port, nil, nil, nil, nil) as it is here:
https://github.com/drbrain/net-http-persistent/blob/c1fb1a5ca29c4c2a7102138af22529cc78adb06e/lib/net/http/persistent.rb#L590C29-L590C32

The instance of Net::HTTP will have nils everywhere for the proxies except for the port number. Thus the changed lines will always show port 80 in the error.

Solution

The proxy? method is used internally to know if there is a proxy, so we can depend on that rather than || the two values:
https://github.com/ruby/ruby/blob/ad4f973ecd0a3481ff1abaa972d457e9f5b5fb4e/lib/net/http.rb#L1786-L1788

Reproduction

> Net::HTTP::Persistent.new.request(URI("http://127.0.0.1:8765"))
Net::HTTP::Persistent::Error: connection refused: 127.0.0.1:80
from /path/lib/net/http/persistent.rb:611:in `rescue in connection_for'
Caused by Errno::ECONNREFUSED: Failed to open TCP connection to 127.0.0.1:8765 (Connection refused - connect(2) for "127.0.0.1" port 8765)

But now with this fix:

> Net::HTTP::Persistent.new.request(URI("http://127.0.0.1:8765"))
Net::HTTP::Persistent::Error: connection refused: 127.0.0.1:8765
from /path/net-http-persistent/lib/net/http/persistent.rb:623:in `rescue in connection_for'
Caused by Errno::ECONNREFUSED: Failed to open TCP connection to 127.0.0.1:8765 (Connection refused - connect(2) for "127.0.0.1" port 8765)