ceph-disk: fix dmcrypt_map() usage for LUKS activate

ceph-disk: fix dmcrypt_map() usage for LUKS activate

29431944c77adbc3464a8faeb7e052b24f821780 added a call to dmcrypt_map()
during disk activation. The change is not suitable for use alongside
the recently added dmcrypt LUKS support, because:
- The callers don't correctly provide cryptsetup_parameters or luks
  arguments.
- dmcrypt_map() calls LuksFormat, which should never be performed
  during disk activation.
- The key file paths don't carry the luks suffix when required.

This commit addresses these issues. Corresponding tests and a udev file
update will follow.

Signed-off-by: David Disseldorp <ddiss@suse.de>
Conflicts:
	src/ceph-disk