[LinuxCNC/linuxcnc Issue#513] HM2 watchdog bite does not cause a pop-up error notifier

Here are the steps I follow to reproduce the issue:

1. Run a Ethernet FPGA card using Axis/LinuxCNC
2. Set the watchdog timeout to a time shorter than the servo period

This is what I expected to happen:

Console report of error and pop-up error on GUI

This is what happened instead:

Got console report of watchdog error but no error pop-up notifier on Axis GUI

It worked properly before this:

Pretty sure this worked under RTAI and got lost in the move to Preempt-RT