Allocate the right amount of memory for 'node' objects
These objects used to have a member of type VECTOR*, but whether memory was actually allocated for that member was determined at run-time (via the 'format', which doesn't exist anymore). The VECTOR* member was removed a while ago, but the run-time size computation was left untouched. This lead to valgrind complaints when load balancing. This commit fixes the size computations.