Fix curl command to support redirect

Merged username-removed-119481 requested to merge miskovic/gitlab-ci-multi-runner:master into master

Original command results in an error:

> curl https://packages.gitlab.com/install/repositories/runner/gitlab-ci-multi-runner/script.deb | sudo bash
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   158    0   158    0     0    244      0 --:--:-- --:--:-- --:--:--   244
bash: line 1: syntax error near unexpected token `<'
bash: line 1: `<html><body>You are being <a href="https://packages.gitlab.com/install/repositories/runner/gitlab-ci-multi-runner/script.deb.sh">redirected</a>.</body></html>'