(SERVER-30) Improve SSL fail-fast for master & CA

The first change in here adds fail-fast behavior to the master service so that it will fail to start if it finds it doesn't have its private key, certificate, and local CA certificate.  If all three of those files are missing, the entire set of SSL files will be generated.

The second change in here loosens the conditions for CA fail-fast so it no longer requires the CA public key, and it will automatically create the signed/ and requests/ directories if they don't exist.
The last `copy` is to put the file back in place so that subsequent iterations don't error on that file.  I could put in a `try/finally`, but either way if an exception is thrown there's not much more to gain by continuing to test the other files so I figured it was mostly unnecessary.