#553 Memory leak in libdwarf

[Joseph Koshy]

This ticket is based on an email from John Kearney dethrophes@gmail.com to elftoolchain-developers:

dwarf_init() allocates an ELF structure internally, but dwarf_elf_init() expects this to be passed in from outside. We need to track whether or not libdwarf had allocated the ELF structure associated with a Dwarf_Debug structure, otherwise we would have a memory leak.