Segfault when scheduler in VERBOSE mode

Switching the scheduler output level to VERBOSE causes a segfault in the creation of the corresponding debug messages:

#6 0x00007f2cfceaf020 in concurrency::DecisionNode::printState(std::__cxx11::basic_stringstream<char, std::char_traits<char>, std::allocator<char> >&, AlgsExecutionStates&, std::vector<int, std::allocator<int> > const&, unsigned int const&) const () from /workdir/gaudi2/build.x86_64-slc6-gcc62-opt/lib/libGaudiHive.so #7 0x00007f2cfcec2b4c in PrecedenceSvc::printState[abi:cxx11](EventSlot&) const () from /workdir/gaudi2/build.x86_64-slc6-gcc62-opt/lib/libGaudiHive.so #8 0x00007f2cfce3f801 in AvalancheSchedulerSvc::dumpSchedulerState(int) () from /workdir/gaudi2/build.x86_64-slc6-ut gcc62-opt/lib/libGaudiHive.so #9 0x00007f2cfce48f9d in AvalancheSchedulerSvc::promoteToScheduled(unsigned int, int, EventContext*) () from /workdir/gaudi2/build.x86_64-slc6-gcc62-opt/lib/libGaudiHive.so

This segfault seems to require multiple event slots, and sub-event slots. Increasing the number of slots and sub-slots (and total events) increases the likelihood of the segfault, which can also (rarely) manifest as an out-of-range exception.

Easily demonstrated by tweaking the config of GaudiHive/options/BasicViewTest.py

Confirmed that it does not occur if dumpSchedulerState() is edited to immediately return rather than executing.