Failure to set multipliers[NPRIMES] was rendering the input-modulus

feature (make sure your prime is not congruent to Foo mod Bar)
largely ineffective. As a result, RSA keys were being generated
every so often with at least one prime congruent to 1 mod 37,
causing modinv(37, phi(n)) to divide by zero, and rightly so. I
believe this fixes `puttygen-zero-div'.

git-svn-id: svn://svn.tartarus.org/sgt/putty@3316 cda61777-01e9-0310-a592-d414129be87e