Can't remove version starting with /

[Zlopez]

In current version of anitya I'm unable to delete version accidentally created in aspell-el project.

The version is prefixed by / which means, that is redirecting to url https://release-monitoring.org/project/16360/delete//aspell6-el-0.08, which is wrong and you end up with getting 404.

This should be easy to fix, just remove this prefix when redirecting to delete page.

[Zlopez]

This is also affecting versions that have / anywhere in their name and versions containing only whitespaces. See https://release-monitoring.org/project/14684/

[luto]

also affects https://release-monitoring.org/project/16134/