Add configurable GRAPHITE_PREFIX

[ Quoting <notifications@github.com> in "Re: [skydns] Add configurable GRAPH..." ]
>> @@ -61,11 +66,10 @@ func init() {
>>
>>  func statsCollect() {
>>  	if graphiteServer != "" {
>> -		addr, err := net.ResolveTCPAddr("tcp", graphiteServer)
>> -		if err != nil {
>> -			go metrics.Graphite(metrics.DefaultRegistry, 10e9, "skydns", addr)
>> -		}
>> +		addr, _ := net.ResolveTCPAddr("tcp", graphiteServer)
>
>Would you want the TCP err != nil then nested in that, or would that be redundant?
>
>```
>if graphiteServer != "" {
>  addr, err := net.LookupHost(graphiteServer)
>    if err != nil {
>      addr, err := net.ResolveTCPAddr("tcp", graphiteServer)
>        if err != nil {
>	  go metrics.Graphite(metrics.DefaultRegistry, 10e9, graphitePrefix, addr)
>        }
>    }
>}
>```

Nested if's like this don't look very Go like, but this is fine for now.

/Miek

-- 
Miek Gieben