undefined method `match' for nil:NilClass when upgrading

Hello! CentOS 6.5, GitLab 7.4.3 CE installed from source.

Trying to upgrade:

sudo service gitlab stop
cd /home/git/gitlab
if [ -f bin/upgrade.rb ]; then sudo -u git -H ruby bin/upgrade.rb; else sudo -u git -H ruby script/upgrade.rb; fi

And I'm getting this:

GitLab 7 upgrade tool
Your version is 7.4.3
/home/git/gitlab/lib/gitlab/upgrader.rb:49:in `latest_version_raw': undefined method `match' for nil:NilClass (NoMethodError)
        from /home/git/gitlab/lib/gitlab/upgrader.rb:38:in `latest_version'
        from /home/git/gitlab/lib/gitlab/upgrader.rb:9:in `execute'
        from bin/upgrade.rb:3:in `<main>'

Firewall and proxy settings are ok. What else should I check?