*NOTE* the changes described in this ticket were over-written by changes made for SERVER-21597.

the connPoolStats command only inspects the "globalConnPool" which stores dbclientinterface style connections. Now that we only use those types of connections in a few places the command is significantly less useful. We should add stats about the NetworkInterface managed connections into its output to make it useful again.

Proposed new output:

There may now be several connection pools in use within the server at any given time. For each connection pool we will report a list of the hosts it contains connections for, and how many of those connections are in use. We'll also provide the total number of connections being made through that pool.

"pools" : {
     "NetworkInterfaceASIO (Sharding)" : {
          "hosts" : {
               "some-server:27017" : {
                        "inUse" : 1,
                        "available" : 2,
                        "created" : 3
                }
          }
          "totalInUse" : 1,
          "totalAvailable" : 2,
          "totalCreated" : 3
     },
     "NetworkInterfaceASIO (Replication)" : { ... },
     "DBClient (Global)" : { ... },
     "ok" : 1
}