isl_transitive_closure.c: avoid use of an unitialized variable on an error path
isl_transitive_closure.c: avoid use of an unitialized variable on an error path

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

epowers/isl,VanirLLVM/toolchain_isl,nicolasvasilache/isl,epowers/isl,PollyLabs/isl,crossbuild/isl,jleben/isl,crossbuild/isl,crossbuild/isl,KangDroidSMProject/ISL,BobSaget-Mod/libisl,simbuerg/isl,VanirLLVM/toolchain_isl,inducer/isl-mirror,pierrotdelalune/isl,nicolasvasilache/isl,BenzoSM/isl,inducer/isl-mirror,epowers/isl,tobig/isl,inducer/isl-mirror,Meinersbur/isl,tobig/isl,nicolasvasilache/isl,jleben/isl,Meinersbur/isl,pierrotdelalune/isl,KangDroidSMProject/ISL,pierrotdelalune/isl,BenzoSM/isl,serge-sans-paille/isl,pierrotdelalune/isl,simbuerg/isl,UBERTC/isl,jleben/isl,evaautomation/isl,jleben/isl,cfx-next/toolchain_isl-upstream,nicolasvasilache/isl,serge-sans-paille/isl,VanirLLVM/toolchain_isl,SaberMod/isl-current,PollyLabs/isl,evaautomation/isl,UBERTC/isl,UBERTC/isl,VanirLLVM/toolchain_isl,simbuerg/isl,epowers/isl,abduld/isl,evaautomation/isl,Meinersbur/isl,Meinersbur/isl,crossbuild/isl,jleben/isl,Distrotech/isl,SaberMod/isl-current,Distrotech/isl,KangDroidSMProject/ISL,simbuerg/isl,BenzoSM/isl,Distrotech/isl,BobSaget-Mod/libisl,inducer/isl-mirror,SaberMod/isl-current,KangDroidSMProject/ISL,BobSaget-Mod/libisl,pierrotdelalune/isl,cfx-next/toolchain_isl-upstream,abduld/isl,abduld/isl,UBERTC/isl,simbuerg/isl,Distrotech/isl,PollyLabs/isl,BenzoSM/isl,VanirLLVM/toolchain_isl,BobSaget-Mod/libisl,epowers/isl,serge-sans-paille/isl,tobig/isl,nicolasvasilache/isl,cfx-next/toolchain_isl-upstream,Distrotech/isl,serge-sans-paille/isl,cfx-next/toolchain_isl-upstream,BenzoSM/isl,BobSaget-Mod/libisl,serge-sans-paille/isl,inducer/isl-mirror,PollyLabs/isl,tobig/isl,PollyLabs/isl,cfx-next/toolchain_isl-upstream,evaautomation/isl,SaberMod/isl-current,abduld/isl,KangDroidSMProject/ISL