kerberos names contain trailing NULL

When calling gssapi import_name function winscp passes in the trailing null. THis is incorrect and blows up the kerberos gss lib I am using.

The problem is here in ssh_gss_import_name

gssbuf.length = sizeof("host@") + strlen(host);

sizeof includes the trailing null on the end of "host@"

I suspect that the MIT kerberos library forgives this error

PS. A really nice product!