[upower] use cor functions to update property

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
no spam

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[connman] refactoring

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>