Plguin btcguild_hashrate_: migrate to Python3

plugins/currency/bitcoin/btcguild_hashrate_

@@ -1,9 +1,9 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # based on https://github.com/pdbrown/munin-custom/blob/master/plugins/hashrate
 # improved by @deveth0 (donation to 1GzHgp9hsDRsf96MnVk2oo6EG1VmWP9jGs :) )
 # usage: link to btcguild_hashrate_YOURAPIKEY
 import sys
-import urllib2
+import urllib.request
 import json
 
 URL = 'https://www.btcguild.com/api.php?api_key='
@@ -18,8 +18,8 @@ if len(sys.argv) > 1:
     command = sys.argv[1]
 
 header = {'User-Agent': 'Mozilla/5.0'}
-request = urllib2.Request(STATS, headers=header)
-mining_stats_raw = urllib2.urlopen(request)
+request = urllib.request.Request(STATS, headers=header)
+mining_stats_raw = urllib.request.urlopen(request)
 mining_stats = json.load(mining_stats_raw)
 workers = mining_stats['workers']