For one, there was a bug here: we cannot "goto error" without setting
the @error variable.
Anyway, restricting "bind" "dbus-client" only to profiles that are
"persist" mode "volatile" seems wrong. The "bind" option as it is,
limits the lifetime of the active-connection. This has no direct relation
with the lifetime of the setting-connection. Indeed, if the
settings-connection's lifetime is itself set to "volatile", then
it will indeed go away with the active-connection. However, these
two concepts are not strictly related.
In the future, we might add an option to limite the lifetime of
a settings-connection to a D-Bus client ("bind-setting"). Possibly
we should thus rename "bind" to "bind-activation", to make the
distinction clearer.