HLT paths for VBFHbb and ZnnHbb

The changes:

- The VBFHbb part in the config file has been uncommented.
- The paths are updated for VBFHbb and ZnnHbb.
- Two lines in the code had to be changed in order to handle the new path names properly.


The increase in size:

subsystem/folder | histograms | bins | Empty bins | Empty/Total | bins per histogram | MB | kB per histogram
------------ | ------------ | ------------ | ------------ | ------------ | ------------ | ------------ | ------------
Higgs before commit | 348 | 16450 | 12264 | 0.746 | 47.3 | 0.0628 | 0.185
Higgs after commit | 426 | 18578 | 14348 | 0.772 | 43.6 | 0.0709 | 0.17

cc: @HuguesBrun, @slehti, @silviodonato