Global Services should **not** reset metric counts

[6a6d74]

Agreed at the Global Services test preparation meeting in Japan - the Guide needs to be amended to reflect this decision.

Global Monitors should implement alerts based on the change in a "count" metric value (i.e., where a metric is incremented following a given event). The absolute value of count metric will vary between Global Services - but the change over a common period should be similar.

Consequently, we would like Global Services to not reset their metric counts arbitrarily - because this would mess up the change comparison by the Global Monitor.

Obviously counts will get reset from time to time (e.g., when the service is restarted, or the the count gets high enough that the it resets itself) - but these events should be infrequent.