isl_affine_hull.c: affine_hull: fix erro handling
isl_affine_hull.c: affine_hull: fix erro handling

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