tree-wide: Use pidref_wait_for_terminate_and_check()

Let's use the pidref variants for waiting and
checking a process everywhere and get rid of the
non pidref variants.

src/machine/machine.c

@@ -1244,7 +1244,7 @@ int machine_copy_from_to_operation(
 
         // TODO: port to PidRef and donate child rather than destroying it
         Operation *operation;
-        r = operation_new(manager, machine, child.pid, errno_pipe_fd[0], &operation);
+        r = operation_new(manager, machine, &child, errno_pipe_fd[0], &operation);
         if (r < 0)
                 return r;