Remove cleanups from coffread.c

Remove cleanups from coffread.c

This removes the remaining cleanups from coffread.c.

Tested by the buildbot and also some manual testing.

This version includes the fix provided by Joel.

gdb/ChangeLog
2019-03-06  Joel Brobecker  <brobecker@adacore.com>
	    Tom Tromey  <tom@tromey.com>

	* stabsread.h (struct stab_section_list): Remove.
	(coffstab_build_psymtabs): Update.
	* dbxread.c (symbuf_sections): Now a std::vector.
	(sect_idx): New global.
	(fill_symbuf): Update.
	(coffstab_build_psymtabs): Change type of stabsects parameter.
	Update.
	* coffread.c (struct coff_symfile_info) <stabsects>: Now a
	std::vector.
	(linetab, linetab_offset, linetab_size, stringtab): Move earlier.
	(coff_locate_sections): Update.
	(coff_symfile_read): Remove cleanups.  Update.
	(init_stringtab): Add storage parameter.
	(free_stringtab, free_stringtab_cleanup): Remove.
	(init_lineno): Add storage parameter.
	(free_linetab, free_linetab_cleanup): Remove.