(change:minor) When setting a new cap, if the new value exceed the max value set it as 0. When getting the current value of cap, return the max value instead of zero
(change:minor) When setting a new cap, if the new value exceed the max value set it as 0. When getting the current value of cap, return the max value instead of zero

sguazt/prometheus,sguazt/dcsxx-testbed,sguazt/prometheus,sguazt/prometheus