Validate and renew should work on non-TGT creds
The validate and renew APIs were using get_cred_from_kdc, which
always presents a TGT to get credentials. Instead, they should
present the ticket they are trying to validate or renew. This is
most easily done with krb5_get_cred_via_tkt(). Move the relevant
code into a new file since it now has nothing in common with the
other APIs implemented in get_creds.c.
ticket: 6699
git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@23891
dc483132-0cff-0310-8789-
dd5450dbe970