Improve Primary's logging about Secondaries.
Improve Primary's logging about Secondaries.

The Primary doesn't "create" Secondaries; it can only register them. And
standardize capitalization.

Signed-off-by: Patrick Vacek <a38520cbbe2e974bc8b7ea86877dd3c7115ca2d7@gmail.com>

advancedtelematic/aktualizr,advancedtelematic/aktualizr,advancedtelematic/aktualizr,advancedtelematic/aktualizr