IPVS collector: Add transport specifier to cluster name, also collect current connection counts.

In some cases, for instance when loadbalancing DNS, it may make sense to have both a UDP and a TCP cluster definitions servicing the same IP and port on both transport protocols. This was poorly supported before, as these two clusters' values would be published to the same metric.

One of these patches prepends all cluster names with their transport protocol and an underscore, to allow this distinction.


The other patch adds collection of the current counts of active and inactive connections, both per backend and the total counts for the virtual instance. This depends on an additional run of ipvsadm, as this info cannot be obtained simultaneously with the --stats argument.

Please note that for setups using Direct Server Return, the active connection counts will tend to be zero.