sanity checks

[flihp]

the ceremony command could use some sanity checks to ensure that the paths to keyspecs and csrspecs exist before we proceed to modify the hsm. Currently if you provide a bad path the directory where the csrspecs are supposed to be the command won't fail till the HSM is already initialized, keys and CA directory structures created. This is a long time to wait for a failure that can be detected much earlier.