[PATCHES] KDC proxy related fixes

[Sumit Bose]

Hi,

it turned out that some of the current SSSD behaviour does not fit well
if a KDC proxy is configured, see
https://fedorahosted.org/sssd/ticket/2652 and
https://fedorahosted.org/sssd/ticket/2700 for details.

The first patch in this series introduces a new call which checks if a
KDC proxy is configured as suggested in the tickets. The other two
patches aim to fix the respective ticket.

bye,
Sumit