Don't access elf tdata in dwarf.c without first checking for an ELF bfd

_bfd_dwarf2_find_nearest_line may be called on a COFF bfd.

	* dwarf2.c (read_address): Check bfd_target_elf_flavour before
	calling get_elf_backend_data.
	(_bfd_dwarf2_find_nearest_line): Fix parens.
Automatic date update in version.in