GSS delegation too eager connection re-use

libcurl would reuse a previously created connection even when the GSS
delegation (CURLOPT_GSSAPI_DELEGATION) option had been changed that could
have changed the user’s permissions in a second transfer.

libcurl keeps previously used connections in a connection pool for subsequent
transfers to reuse if one of them matches the setup. However, this GSS
delegation setting was left out from the configuration match checks, making
them match too easily, affecting krb5/kerberos/negotiate/GSSAPI transfers.