Fix 'winadj-success': since at least one server (boks_sshd) blithely responds
to "winadj@putty.projects.tartarus.org" with SSH_MSG_CHANNEL_SUCCESS despite
probably having no idea what it means, treat this just the same as
SSH_MSG_CHANNEL_FAILURE instead of killing the connection.
Tested only as far as making sure that winadj/FAILURE with a normal server
isn't _completely_ broken.
[originally from svn r9185]
[this svn revision also touched putty-wishlist]