[krbdev.mit.edu #8587] ktutil addent should be able to fetch etype-info2 for principal

[Greg Hudson via RT]

At the moment, ktutil addent requires you to specify the enctype and 
salt (if it's not the default), and it just can't work if there are 
s2kparams or a salt that can't be written as a C string on the command 
line.  There should be an option to fetch the etype-info2 value for 
the principal from the KDC and use that.

To do this we need a new library interface, probably an extension of 
the get_init_creds interfaces, to make an AS-REQ and extract the 
etype-info2 from either the AS-REP or PREAUTH_REQUIRED error response.

(You also have to specify a kvno to ktutil addent.  That information 
is available from the KDC if it issues a ticket and includes a kvno in 
the EncryptedData, but not if preauth is required for the principal or 
if the KDC just doesn't include a kvno when issuing a ticket.  So I 
don't think it's worth the complexity of even trying to fetch it.)