[Rivet] Segmentation fault when running agile-runmc on the grid

[David Grellscheid]

> If you would find this useful (anyone, including other Rivet list
> members!) then please add a supporting comment on that Savannah ticket!

Generator-dependent annotations in HepMC? Why is that a good idea? The 
whole beauty of the Rivet approach is the independence from any 
non-physical considerations.

   David