remote: consistently use flags for passing ro/user/autostart props

remote: consistently use flags for passing ro/user/autostart props

We have helper methods that return boolans for ro/user/autostart
properties. We then pack them into a flags parameter, and later
unpack them again. This makes the code consistently use flags
throughout.

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>