Add SSH-1 password camouflage bug detection for version OSU_1.4alpha3 of the

Add SSH-1 password camouflage bug detection for version OSU_1.4alpha3 of the
OSU VMS SSH server <http://kcgl1.eng.ohio-state.edu/~jonesd/ssh/>.

The changelog appears to indicate that the server was fixed for pwplain1 at
1.5alpha4, and for IGNORE and DEBUG messages at 1.5alpha6. However I'm going
to go on the reports we've had as I haven't tested this; and they indicate
only that 1.5alpha6 is known not to require any bug compatibility modes.

(I wasn't sure whether to add this at all, given that upgrading to version
OSU_1.5alpha6 is an easy way to fix the problem. However, there is precedent
for adding detection for old versions of servers which have since been fixed.)

git-svn-id: svn://svn.tartarus.org/sgt/putty@3359 cda61777-01e9-0310-a592-d414129be87e