Add possibility to build mctester without hepmc2

5 jobs for mctester-update in 9 minutes and 30 seconds (queued for 19 seconds)
latest
Status Name Job ID Coverage
  Test
passed cc7 #15115503

00:06:30

passed fedora30 #15115505

00:03:05

passed mac #15115506

00:06:23

passed slc6 #15115502

00:05:44

passed ubuntu18 #15115504

00:03:01