Security Update: httpclient library to latest version (2.5.1)

This is a security patch. With the latest version of httpclient, if you
use this gem in an app already using httpclient, you will still be able
to apply the security patch referenced here:

https://github.com/nahi/httpclient/issues/202#issuecomment-59154062

Basically, I cannot use this gem as it is currently and have a newer version
of httpclient used in my app, which allows me to apply the POODLE ssl fix.