Don't set the internal service discovery state twice to the same

The first call is not necessary as nothing has changed in the meantime.

Change-Id: I8db51fd725dd210b3d5c7b01d399d24877bf9b2f
Reviewed-by: Aaron McCarthy <mccarthy.aaron@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>