Nuget V3 - Impossible to use hosted/group/proxy as remote for proxy

Scenario

1. Create hosted or group or proxy repo
2. Create proxy repo with just created repository as remote
3. Try to install any library, angularjs for example

Actual: 

Unable to load the service index for source http://localhost:8081/repository/nuget-proxy3/index.json.
  Response status code does not indicate success: 404 (Not Found).

Expected: Service index was fetched and the package was installed

Looks like this is problem in proxy side, because proxy builds

remote url = http://localhost:8081/repository/nuget-hosted/index.json/
but real remote url DOES NOT endwith "/" = http://localhost:8081/repository/nuget-hosted/index.json

Default repository(https://api.nuget.org/v3/index.json) works with slashes at the end(https://api.nuget.org/v3/index.json/), so we can change regexp and add the slash as an optional value