Update shebang of Python3-compatible plugins to Python3

plugins/currency/ethereum/ethermine_hashrate_

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """
 =head1 NAME
@@ -42,20 +42,13 @@ GPLv2
 =cut
 """
 
-from __future__ import print_function
 
 import sys
 import json
 import codecs
 
-try:
-    # python3
-    from urllib.request import urlopen
-    from urllib.request import Request
-except ImportError:
-    # python2
-    from urllib2 import urlopen
-    from urllib2 import Request
+from urllib.request import urlopen
+from urllib.request import Request
 
 command = ''
 if len(sys.argv) > 1:

plugins/network/sockstat-via-procfs

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import re
 import sys

plugins/other/ksm_

@@ -1,5 +1,4 @@
-#!/usr/bin/env python
-# -*- encoding: UTF-8 -*-
+#!/usr/bin/env python3
 #
 # ksm
 #

plugins/percona/percona_

@@ -1,6 +1,4 @@
-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-# vim: set fileencoding=utf-8
+#!/usr/bin/env python3
 #
 # Munin plugin for Percona XtraDB Cluster. Monitors values of these cluster replication variables:
 # percona_queues: wsrep_local_recv_queue, wsrep_local_send_queue

plugins/security/fail2ban_

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """
 =head1 NAME

plugins/ubuntu/apt_ubuntu

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # -*- encoding: iso-8859-1 -*-
 #
 # apt_ubuntu

plugins/weather/weather_

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import os
 import re