Properties set pre-connect should be set via ConfigureProperty

With a REIS intermediate in place (e.g. portal), the initial set of messages sent to the EIS implementation may look like this:

### portal obtains the fd
ConfigureName
ConfigureCapabilities
Property
Property
### portal passes fd to libei client
Connect
Property
...

Properties are the obvious one sticking out here, they're not part of the Configure* messages. In the case where the portal keeps the file descriptor open, it could write property events after the client connects, messing up the client. The EIS implementation cannot distinguish the two.