Make sure there's only one slash as path separator
In Ruby 2.4, URI.join("http://test//", "a").to_s will
remove the double slash, however it's not the case in
Ruby 2.5. Using chomp should work better for the intention,
as we're not trying to allow things like ../ or / paths
resolution.
EE port: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8084