s3-winbind: Fix Bug #7568: Make sure cm_connect_lsa_tcp does not reset the secure...

s3-winbind: Fix Bug #7568: Make sure cm_connect_lsa_tcp does not reset the secure channel.

This is an important fix as the following could and is happening:

* winbind authenticates a user via schannel secured netlogon samlogonex call,
current secure channel cred state is stored in winbind state, winbind
sucessfully decrypts session key from the info3

* winbind sets up a new schannel ncacn_ip_tcp lsa pipe (and thereby resets the
secure channel on the dc)

* subsequent samlogonex calls use the new secure channel creds on the dc to
encrypt info3 session key, while winbind tries to use old schannel creds for
decryption

Guenther