Remove buildsym_new_init

Remove buildsym_new_init

buildsym_new_init is just an alias for buildsym_init.  This removes
it.  In the long run buildsym_init will also go away; this patch just
helps make things a bit clearer in the meantime.

gdb/ChangeLog
2018-07-16  Tom Tromey  <tom@tromey.com>

	* xcoffread.c (xcoff_new_init): Update.
	* mipsread.c (mipscoff_new_init): Update.
	* mdebugread.c (mdebug_build_psymtabs): Update.
	* elfread.c (elf_new_init): Update.
	* dbxread.c (dbx_new_init, coffstab_build_psymtabs)
	(elfstab_build_psymtabs, stabsect_build_psymtabs): Update.
	* buildsym.h (buildsym_new_init): Don't declare.
	* buildsym.c (buildsym_new_init): Remove.