Validate parameters for vault operator init

[akshya96]

https://hashicorp.atlassian.net/browse/VAULT-951

The "vault operator" command should not operate if there are unused command-line flags, for example:
vault operator init --recovery-threshold=1 --recovery-shares=1
should return an error because auto unseal is not being used (the correct flags are -key-shares and -key threshold.)

[ncabatoff]

I agree that you have to remove the defaults from the flag definitions, but I wouldn't push everything into the api as you're doing. People often use different versions of the CLI and server, and this could break backwards compat.

We might have to make the operator init command query the sys/seal-status endpoint to determine whether shamir is in use or not, so it can make the right decision about which defaults to use when the user doesn't specify any share/threshold flags.

[akshya96]

I agree that you have to remove the defaults from the flag definitions, but I wouldn't push everything into the api as you're doing. People often use different versions of the CLI and server, and this could break backwards compat.

We might have to make the operator init command query the sys/seal-status endpoint to determine whether shamir is in use or not, so it can make the right decision about which defaults to use when the user doesn't specify any share/threshold flags.

I agree, I did not think of different versions of cli and server. I have changed the cli to set default values based on use of auto unseal instead of setting default values for all fields.

[ccapurso]

Looks good!

[akshya96]

Added a new unit test for auto unseal

[ccapurso]

Tests look good!