Do not complain that there is no OpenCL or CUDA worker

tests/datawizard/readonly.c

@@ -73,6 +73,5 @@ enodev:
 	starpu_shutdown();
 	/* yes, we do not perform the computation but we did detect that no one
 	 * could perform the kernel, so this is not an error from StarPU */
-	fprintf(stderr, "WARNING: No one can execute this task\n");
 	return STARPU_TEST_SKIPPED;
 }

tests/parallel_tasks/cuda_only.c

@@ -106,7 +106,6 @@ enodev:
 	task->destroy = 0;
 	starpu_task_destroy(task);
 	starpu_data_unregister(handle);
-	fprintf(stderr, "WARNING: No one can execute this task\n");
 	/* yes, we do not perform the computation but we did detect that no one
  	 * could perform the kernel, so this is not an error from StarPU */
 	starpu_shutdown();