Setting ssl version fails, update httpi gem to v2.2

Setting ssl version fails because of a [bug](https://github.com/savonrb/httpi/pull/109) in [httpi](https://github.com/savonrb/httpi) gem. As it's fixed now, httpi gem version update is required.

```ruby
require 'savon'
Savon.client(wsdl: 'https://example.endpoint.with.tls/wsdl', ssl_version: :TLSv1).operations
```

```ruby
HTTPI::SSLError: SSL_connect returned=1 errno=0 state=SSLv3 read server hello A: sslv3 alert handshake failure
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/httpi-2.1.0/lib/httpi/adapter/httpclient.rb:28:in `rescue in request'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/httpi-2.1.0/lib/httpi/adapter/httpclient.rb:25:in `request'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/httpi-2.1.0/lib/httpi.rb:140:in `request'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/httpi-2.1.0/lib/httpi.rb:106:in `get'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/wasabi-3.3.0/lib/wasabi/resolver.rb:43:in `load_from_remote'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/wasabi-3.3.0/lib/wasabi/resolver.rb:33:in `resolve'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/wasabi-3.3.0/lib/wasabi/document.rb:142:in `xml'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/wasabi-3.3.0/lib/wasabi/document.rb:160:in `parse'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/wasabi-3.3.0/lib/wasabi/document.rb:147:in `parser'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/wasabi-3.3.0/lib/wasabi/document.rb:64:in `soap_actions'
	from /home/kaa/.rvm/gems/ruby-2.0.0-p195@roombeats/gems/savon-2.5.1/lib/savon/client.rb:28:in `operations'
	from (irb):2
	from /home/kaa/.rvm/rubies/ruby-2.0.0-p195/bin/irb:12:in `<main>'
```