make clean isn't cleaning /var/lib/dkms/iomemory-vsl4/v5.6.0/build/ on Fedora 30

[Tourman36]

Steps to reproduce:

git checkout code-cleanup
make dkms
make clean
git checkout fix-cpus_mask
make dkms

... compile still fails

/var/lib/dkms/iomemory-vsl4/v5.6.0/build/kcpu.c: In function ‘__kfio_bind_task_to_cpumask’:
/var/lib/dkms/iomemory-vsl4/v5.6.0/build/kcpu.c:128:8: error: ‘struct task_struct’ has no member named ‘cpus_mask’
  128 |     tsk->cpus_mask = *mask;
      |        ^~

git diff:

--- a/var/lib/dkms/iomemory-vsl4/v5.6.0/build/kcpu.c
+++ b/root/usr/src/iomemory-vsl4-4.3.7/kcpu.c
@@ -125,7 +125,12 @@ int kfio_create_kthread_on_cpu(fusion_kthread_func_t func, void *data,

 static void __kfio_bind_task_to_cpumask(struct task_struct *tsk, cpumask_t *mask)
 {
+
+#if KFIOC_X_TASK_HAS_CPUS_MASK
     tsk->cpus_mask = *mask;
+#else
+    tsk->cpus_allowed = *mask;
+#endif
     tsk->nr_cpus_allowed = cpumask_weight(mask);
 }

[snuf]

fix for dkms correct versioning is in #15