Fix D-Bus calls in KernelKey context manager
Fix D-Bus calls in KernelKey context manager

They were using mix of dbus-python and dbus-python-client-gen
constructions. They are now pure dbus-python.

Signed-off-by: mulhern <7b51bcf507bcd7afb72bf8663752c0ddbeb517f6@redhat.com>

stratis-storage/stratis-cli,stratis-storage/stratis-cli