Auto merge of #5638 - bundler:seg-warn-old-tls, r=indirect

Warn when making an outdated TLS connection to rubygems.org

Right now, output looks like

```
Your Ruby version does not support TLSv1.1 or newer, which will be required to connect to https://index.rubygems.org by June 2018.
Fetching gem metadata from https://rubygems.org/...........
Fetching version metadata from https://rubygems.org/..
Resolving dependencies...
Using rake 11.3.0
Using automatiek 0.1.2 from source at `.`
Using rspec-support 3.5.0
Using diff-lcs 1.3
Using bundler 1.15.0.pre.3
Using rspec-core 3.5.4
Using rspec-expectations 3.5.0
Using rspec-mocks 3.5.0
Using rspec 3.5.0
Bundle updated!
```

Obviously this requires tests, and also backing out forcing the TLS version (which I did to make testing easier). The message could also use improvement, but I figured I'd ask for input from @indirect and @dwradcliffe

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/bundler/fetcher.rb b/lib/bundler/fetcher.rb
index 5a9617c60a..03ff528826 100644
--- a/lib/bundler/fetcher.rb
+++ b/lib/bundler/fetcher.rb
@@ -238,7 +238,7 @@ module Bundler
           Bundler.settings[:ssl_client_cert]
         raise SSLError if needs_ssl && !defined?(OpenSSL::SSL)
 
-        con = Bundler::Persistent::Net::HTTP::Persistent.new "bundler", :ENV
+        con = PersistentHTTP.new "bundler", :ENV
         if gem_proxy = Bundler.rubygems.configuration[:http_proxy]
           con.proxy = URI.parse(gem_proxy) if gem_proxy != :no_proxy
         end
@@ -277,7 +277,7 @@ module Bundler
       Timeout::Error, EOFError, SocketError, Errno::ENETDOWN, Errno::ENETUNREACH,
       Errno::EINVAL, Errno::ECONNRESET, Errno::ETIMEDOUT, Errno::EAGAIN,
       Net::HTTPBadResponse, Net::HTTPHeaderSyntaxError, Net::ProtocolError,
-      Bundler::Persistent::Net::HTTP::Persistent::Error, Zlib::BufError, Errno::EHOSTUNREACH
+      PersistentHTTP::Error, Zlib::BufError, Errno::EHOSTUNREACH
     ].freeze
 
     def bundler_cert_store