Ensure that even 127.*.*.* Ruby traffic is proxied

It turns out that Ruby's default URI implementation explicitly
disables this, and doesn't document that. We now override
the find_proxy method completely, so it *always* uses the
HTK proxy.

Author: pimterry

overrides/gems/uri/generic.rb

@@ -0,0 +1,18 @@
+# Remove this module from LOAD_PATH, so we can load the real one
+gem_override_path = File.expand_path('..', __dir__) # parent dir, we're a subfolder
+$LOAD_PATH.reject! { |path| File.expand_path(path) == gem_override_path }
+
+# Load uri/generic, and inject our proxy settings as the default for all requests
+require 'uri/generic'
+module URI
+    class Generic
+        def find_proxy
+            # Real code for this avoids it in various cases, if some CGI env vars
+            # are set, or for 127.*.*.* requests. We want to ensure we use it always.
+            URI.parse(ENV['HTTP_PROXY'])
+        end
+    end
+end
+
+# Put this override directory back on LOAD_PATH
+$LOAD_PATH.unshift(gem_override_path)