parasite-syscall: Don't invert the sign of parasite return code

This sneaked during parasite error handling code rework.
When parasite returned negative error code we should not
invert it.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

parasite-syscall.c

@@ -225,7 +225,7 @@ static int parasite_execute_by_pid(unsigned int cmd, struct parasite_ctl *ctl, p
 
 	ret = __parasite_execute(ctl, pid, &regs);
 	if (ret == 0)
-		ret = -(int)regs.ax;
+		ret = (int)regs.ax;
 
 	if (ret)
 		pr_err("Parasite exited with %d\n", ret);