isl_constraint_add_div: correctly set line to first and only constraint
isl_constraint_add_div: correctly set line to first and only constraint

When isl_constraint_add_div was introduced in 3fcebd4 (isl_constraint:
add limited support for adding divs), the equalities were still placed
before the inequalities in the constraint matrix.
This changed in 9eb1488 (isl_basic_map: put inequalities before equalities),
but the implementation of isl_constraint_add_div was not adapted accordingly.
This has probably gone unnoticed because isl_constraint_add_div has only
been used on equality constraints.

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