Open the PAC socket from krb5_child before dropping root
The PAC responder by default allows only connections from the root user.
This patch opens the socket to the PAC responder before the krb5_child
drops privileges so the connection seemingly comes from root.
Reviewed-by: Sumit Bose <email@example.com>
(cherry picked from commit 858e750c3d4fe54e50616a1ed1e101469503c070)