When asked to both use a `.netrc` file for credentials and to follow HTTP redirects, curl could leak...

When asked to both use a .netrc file for credentials and to follow HTTP redirects, curl could leak the password used for the first host to the followed-to host under certain circumstances.

This flaw only manifests itself if the netrc file has an entry that matches the redirect target hostname but the entry either omits just the password or omits both login and password.