SSL error on update 6.0 -> 6.2:

Created by: frlan

On update from 6.0 to 6.2 I'm receiving this message when running:

sudo -u git -H bundle install --without development test mysql --deployment

[...]

 Bundler::Fetcher::CertificateFailureError: Could not verify the SSL certificate for 
 https://rubygems.org/.
 There is a chance you are experiencing a man-in-the-middle attack, but most 
 likely your system doesn't have the CA certificates needed for verification. For 
 information about OpenSSL certificates, see bit.ly/ruby-ssl. To connect without 
 using SSL, edit your Gemfile sources and change 'https' to 'http'.
 An error occurred while installing carrierwave (0.8.0), and Bundler cannot 
 continue.
 Make sure that `gem install carrierwave -v '0.8.0'` succeeds before bundling.

This happened on Ubuntu 12.04 x64 at af2ee9b0 -- on a second try it worked however.