isl_id.c: isl_id_has_name_and_user: handle missing name on one isl_id
isl_id.c: isl_id_has_name_and_user: handle missing name on one isl_id

If the name is missing on only one of the isl_ids, then we may
end up comparing the other name to NULL.

Detected by a scan_build on Polly

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

Meinersbur/isl,evaautomation/isl,PollyLabs/isl,evaautomation/isl,Meinersbur/isl,SaberMod/isl-current,KangDroidSMProject/ISL,SaberMod/isl-current,nicolasvasilache/isl,SaberMod/isl-current,crossbuild/isl,PollyLabs/isl,tobig/isl,tobig/isl,Distrotech/isl,BenzoSM/isl,KangDroidSMProject/ISL,simbuerg/isl,BenzoSM/isl,UBERTC/isl,abduld/isl,BenzoSM/isl,BenzoSM/isl,nicolasvasilache/isl,abduld/isl,PollyLabs/isl,Meinersbur/isl,nicolasvasilache/isl,crossbuild/isl,crossbuild/isl,evaautomation/isl,nicolasvasilache/isl,KangDroidSMProject/ISL,KangDroidSMProject/ISL,inducer/isl-mirror,simbuerg/isl,simbuerg/isl,Meinersbur/isl,UBERTC/isl,BenzoSM/isl,PollyLabs/isl,evaautomation/isl,abduld/isl,tobig/isl,inducer/isl-mirror,tobig/isl,inducer/isl-mirror,inducer/isl-mirror,abduld/isl,UBERTC/isl,nicolasvasilache/isl,inducer/isl-mirror,PollyLabs/isl,Distrotech/isl,Distrotech/isl,KangDroidSMProject/ISL,UBERTC/isl,simbuerg/isl,Distrotech/isl,crossbuild/isl,Distrotech/isl,SaberMod/isl-current,simbuerg/isl