[DLR] Device does not forward SignOn frame sporadically after power up

This is aback port of PSEIP-639.

Sporadically, the device does not forward the SignOn frame although the ring state is NORMAL.

Evaluation:

The SignOn frame is received and the DLR state machine is also in the expected state NORMAL, but when the SingOn shall be forwarded, the link state stored in DLR resources is still "Link Down", which prevents the frame of being sent by the DLR state machine.