[Bro-Dev] Segfault in TM

[Matthias Vallentin]

(I'm sending this as email because the TM tracker does not work for me:
the project has no components, which prevents filing an issue.)

Ahir consistently ran into segmentation faults with his workload. We
debugged the issue and found the culprit: In FifoDisk.cc, a call
std::vector<T>::front() violates the precondition

    ! std::vector<T>::empty()
    
and thus causes UB. I fixed this here:

    https://github.com/mavam/time-machine
    
It's a one-line fix and ready to merge.

   Matthias