Padding on the end of the encrypted data in OpenSSH key format was

Padding on the end of the encrypted data in OpenSSH key format was
broken: the OpenSSL EVP layer specifies a very particular form of
padding, which I wasn't generating because it hadn't occurred to me
that it might be mandatory. Irritatingly this was causing our
exported OpenSSH keys to load perfectly happily back in through our
OpenSSH import routines, but to be rejected by OpenSSH proper. Sigh.

git-svn-id: http://svn.tartarus.org/sgt/putty@1733 cda61777-01e9-0310-a592-d414129be87e