isl_ast.c: remove more remnants of code removed before inclusion
isl_ast.c: remove more remnants of code removed before inclusion

This was missing from 0103207 (isl_ast_codegen.c: remove remnants of code
removed before inclusion, Thu Jul 31 09:07:35 2014 +0200).

Signed-off-by: Sven Verdoolaege <e5350bbed4977f5eb8ae1dc6abd9ae59d21ace75@kotnet.org>

PollyLabs/isl,nicolasvasilache/isl,PollyLabs/isl,PollyLabs/isl,nicolasvasilache/isl,tobig/isl,UBERTC/isl,inducer/isl-mirror,UBERTC/isl,nicolasvasilache/isl,PollyLabs/isl,Meinersbur/isl,inducer/isl-mirror,tobig/isl,Meinersbur/isl,inducer/isl-mirror,Meinersbur/isl,inducer/isl-mirror,PollyLabs/isl,tobig/isl,inducer/isl-mirror,UBERTC/isl,UBERTC/isl,nicolasvasilache/isl,nicolasvasilache/isl,Meinersbur/isl,tobig/isl