libctf: eschew C99 for loop initial declarations

We shouldn't use these, since binutils doesn't require a C99-capable
compiler yet.

New in v3.
v5: fix tabdamage.

libctf/
	* ctf-open.c (flip_lbls): Eschew for-loop initial declarations.
	(flip_objts): Likewise.
	(flip_vars): Likewise.
	(flip_types): Likewise.