Use correct name-type in TGS-REQs for 2008R2 RODCs

Use correct name-type in TGS-REQs for 2008R2 RODCs

Correctly set the name-type for the TGS principals to KRB5_NT_SRV_INST
in TGS-REQs.  (Previously, only AS-REQs had the name-type set in this
way.)  Windows Server 2008 R2 read-only domain controllers (RODCs)
insist on having the correct name-type for the TGS principal in
TGS-REQs as well as AS-REQs, at least for the TGT-forwarding case.

Thanks to Sebastian Galiano for reporting this bug and helping with
testing.

ticket: 7120
target_version: 1.10.2
tags: pullup

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@25839 dc483132-0cff-0310-8789-dd5450dbe970