Add pwdf retry logic to OpenSSHKeyV1KeyFile

[fmeum]

While PKCS8KeyFile uses PasswordFinder's shouldRetry to determine
whether it should call reqPassword again if decryption of they key file
fails, OpenSSHKeyV1KeyFile simply gives up and throws an exception.

With this commit, retry logic similar to that of PKCS8KeyFile is added
to OpenSSHKeyV1KeyFile. The PasswordFinder's reqPassword is called
again if the validation of the "checkint" fails, which indicates an
incorrect passphrase.

[fmeum]

I think that the CI fails here and in #586 are due to 3526694. I confirmed that this builds and retries correctly locally, but some unit tests fail due to seemingly unrelated Mockito exceptions.

[hierynomus]

I think that the CI fails here and in #586 are due to 3526694. I confirmed that this builds and retries correctly locally, but some unit tests fail due to seemingly unrelated Mockito exceptions.

The CI failures are indeed due to that change. Have to dive into it why this happens.

[fmeum]

The second commit replaces EncryptionException with a new exception type defined as an inner class.

[hierynomus]

I've merged master into this PR, in order to fix the builds.

[hierynomus]

Thanks!