Target Windows Vista in leash/stdafx.h

Define WINVER and _WIN32_WINNT, to target Vista+ -- required for
ribbon ui.

Signed-off-by: Kevin Wasserman <kevin.wasserman@painless-security.com>

(cherry picked from commit fed20805254a9b49c7e75ba83de2a95348b21c3b)

https://github.com/krb5/krb5/commit/c15be9b91293b12bb78d39c817afd04d021c3af9
Author: Kevin Wasserman <kevin.wasserman@painless-security.com>
Committer: Tom Yu <tlyu@mit.edu>
Commit: c15be9b91293b12bb78d39c817afd04d021c3af9
Branch: krb5-1.10
 src/windows/leash/StdAfx.h |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)