Fix: display online_cpus in compat REST API

Signed-off-by: Boaz Shuster <boaz.shuster.github@gmail.com>

libpod/stats_common.go

@@ -47,3 +47,8 @@ func (c *Container) GetContainerStats(previousStats *define.ContainerStats) (*de
 	}
 	return stats, nil
 }
+
+// GetOnlineCPUs returns the number of online CPUs as set in the container cpu-set using sched_getaffinity
+func GetOnlineCPUs(container *Container) (int, error) {
+	return getOnlineCPUs(container)
+}