modules/certs: fix nss import error

Private keys generated with `certtool --generate-privkey` are no longer
accepted by pk12util (nss) after its recent upgrade.

It is unclear to me why. The tools fails with a rather ambiguous message:

  pk12util: PKCS12 decode import bags failed:
  SEC_ERROR_PKCS12_UNABLE_TO_IMPORT_KEY: Unable to import.  Error
  attempting to import private key.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
cloud-init: Remove dead code

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
cloud-init/cassandra: Fix logging printout

The key/value printout is missing an quotation mark after the value.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>