* dwarf2.c (read_abbrevs): If bfd_realloc fails, free currently allocated memory

* dwarf2.c (read_abbrevs): If bfd_realloc fails, free currently allocated memory
  before returning.
  (decode_line_info): Likewise.
  (_bfd_dwarf2_cleanup_debug_info): New function:  Frees memory	allocated by
  functions in this file.
* elf-bfd.h (_bfd_dwarf2_cleanup_debug_info): Prototype.
* elf.c (bfd_elf_close_and_cleanup): Call _bfd_dwarf2_cleanup_debug_info.