Please take a look at http://cr.openjdk.java.net/~weijun/8001208/webrev.00/
An old test is enhanced to check for the fix.Honestly, it might be best to check for KRB5CCNAME outside FileCredentialsCache since the ccache type can be something other than FILE:. It will touch more files and I decide to delay this enhancement until we start supporting more real types.
Also, I want to backport this fix to 7u, so it had better be simple. Thanks Max
