Fix missing empty line
Fix a possible memory leak
Replace calloc by malloc

Why calloc at all?
Remove obsolete test of llist

The llist comes from the previous dtree_procfs implementation.
It does not exist anymore...
Fix test_pass_file for the new procfs implementation

The new implementation does not accept a file as the
root directory and it is considered to be an error now.
Merge branch 'maintenance-fixes'

* maintenance-fixes:
  Fix test_pass_file for the new procfs implementation
  Remove obsolete test of llist
  Replace calloc by malloc
  Fix a possible memory leak
  Fix missing empty line
Add GNU LGPLv3 license