samples: Apply password for signing key when creating platform cert (bugfix)

Apply the password for the signing key and parent key when creating a
platform certificate. The bug was introduced in commit 961bb827
"samples: Use new pwd format option for secretly passing passwords"

Extend a test case to ensure that the passwords are always used.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
2 files changed