log-courier: proper configuration with confd

[icc-bloe]

To avoid malformed JSON file due to a trailing comma at the end of the server entries currently there is an empty server ("") set in the configuration file.
Log-courier does not crash because of this but it complains repeadeatly about incorrect set port:

Transport init failed: Invalid hostport given:

The problem with confd:

{
    "server1:port1",
    "server2:port2",
}

because it is defined like:

{
    'foreach server print' -> $servername:$port ,
}

Should be:

{
    "server1:port1",
    "server2:port2"
}

Current workaround:

{
    "server1:port1",
    "server2:port2",
    ""
}

because:

{
    'foreach server print' -> $servername:$port ,
    ""
}