wsk should remove trailing slash on apihost

Just spent an embarrassing amount of time trying to determine why the wsk CLI was working on one machine and not on another. The ultimate issue was that I ended up specifying the `APIHOST` variable as `https://localhost:8443/` in the config file, with the trailing slash, which causes 404s since the CLI was sending requests to `https://localhost:8443//api/v1/namespaces/_/triggers?limit=0&skip=0` (note the double-slash after the domain).

Comienza rastreando cómo la CLI lee la configuración de APIHOST y construye las URL de las solicitudes. Reproduce el caso de la barra final y verifica después que las solicitudes usen un único separador y que la ruta de API afectada ya no devuelva un 404.

Escrito por el modelo de indexación a partir del texto del issue.