Use of qualifier loose client configuration

[clmath]

After the changes in #642, client configuration is lost when a qualifier is used.
It seems that configuration are registered to the qualifier but resolved using the client name.

Sample :

@ReactiveFeignClient(name = "auth-server", configuration = AuthConfig.class, qualifier = "auth-client-with-config")
public interface AuthClient {
    // AuthConfig is ignored
}

If you use the same value for name and qualifier, the configuration is working as expected.

See also #673