extract into Bundler.ruby_version
add Bundler::RubyVersion#host
include the unknown engine's name
add user agent to fetcher requests
also include host data in the user agent
on JRuby, RbConfig::CONFIG["host"] doesn't exist
default requests have "Ruby" in the user-agent
init the connection once
set user agent without "Ruby, "
random id to correlate requests in one run
Add command to user agent for fetcher requests

Checks bundler, rubygems, ruby, command
Merge pull request #2649 from joyicecloud/user_agent

Add user agent to fetcher requests
just send the command name in the user agent
NHP handles no SSL now