Experiment continues running with errors and no transmitted work

[allenz1120]

This occured when we were running 4VMs. The beaglebones were on in the lab so that's why it was showing up with unknown devices but after >40 mins, no functions were being ran and it never ended.

[abyrne55]

This may have been due to a gap in the Worker state machine where workers could get stuck in the REBOOTING state. I've patched that gap by adding a self-transition on REBOOTING guarded by "WR2&QNE" that activates the "reboot" output, as shown in the diagram below:

Let's keep an eye out for this bug during this week's runs. We can close this issue one it stops popping up.