Update lib/net/http/generic_request.rb

Co-authored-by: Sorah Fukumori <sora134@gmail.com>

Author: taketo1113

lib/net/http/generic_request.rb

@@ -246,7 +246,7 @@ def update_uri(addr, port, ssl) # :nodoc: internal use only
     end
 
     if host = self['host']
-      host = URI.parse("#{scheme}://#{host}").host
+      host = URI.parse("//#{host}").host # Remove a port component from the existing Host header
     elsif host = @uri.host
     else
      host = addr