Bring ceph-osd to Python 3

* Synced version of charm-helpers
* Synced version of charms.ceph to bring in Py3 compatible library
  methods.

Change-Id: I5ac45740f48a71d9cb0c5943472fc8590a723514

hooks/ceph_hooks.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 #
 # Copyright 2016 Canonical Ltd
 #
@@ -304,7 +304,7 @@ JOURNAL_ZAPPED = '/var/lib/ceph/journal_zapped'
 
 def read_zapped_journals():
     if os.path.exists(JOURNAL_ZAPPED):
-        with open(JOURNAL_ZAPPED) as zapfile:
+        with open(JOURNAL_ZAPPED, 'rt', encoding='UTF-8') as zapfile:
             zapped = set(
                 filter(None,
                        [l.strip() for l in zapfile.readlines()]))
@@ -318,7 +318,7 @@ def write_zapped_journals(journal_devs):
     with os.fdopen(tmpfh, 'wb') as zapfile:
         log("write zapped: {}".format(journal_devs),
             level=DEBUG)
-        zapfile.write('\n'.join(sorted(list(journal_devs))))
+        zapfile.write('\n'.join(sorted(list(journal_devs))).encode('UTF-8'))
     shutil.move(tmpfile, JOURNAL_ZAPPED)
 
 
@@ -399,8 +399,7 @@ def get_mon_hosts():
             if addr:
                 hosts.append('{}:6789'.format(format_ipv6_addr(addr) or addr))
 
-    hosts.sort()
-    return hosts
+    return sorted(hosts)
 
 
 def get_fsid():
@@ -446,9 +445,8 @@ def get_devices():
     devices.extend((storage_get('location', s) for s in storage_ids))
 
     # Filter out any devices in the action managed unit-local device blacklist
-    return filter(
-        lambda device: device not in get_blacklist(), devices
-    )
+    _blacklist = get_blacklist()
+    return [device for device in devices if device not in _blacklist]
 
 
 def get_journal_devices():
@@ -460,12 +458,9 @@ def get_journal_devices():
     devices.extend((storage_get('location', s) for s in storage_ids))
 
     # Filter out any devices in the action managed unit-local device blacklist
-    devices = filter(
-        lambda device: device not in get_blacklist(), devices
-    )
-    devices = filter(os.path.exists, devices)
-
-    return set(devices)
+    _blacklist = get_blacklist()
+    return set(device for device in devices
+               if device not in _blacklist and os.path.exists(device))
 
 
 @hooks.hook('mon-relation-changed',
@@ -496,7 +491,7 @@ def upgrade_charm():
             'nrpe-external-master-relation-changed')
 def update_nrpe_config():
     # python-dbus is used by check_upstart_job
-    apt_install('python-dbus')
+    apt_install('python3-dbus')
     hostname = nrpe.get_nagios_hostname()
     current_unit = nrpe.get_nagios_unit_name()
     nrpe_setup = nrpe.NRPE(hostname=hostname)