update default_log_levels set by ceilometer

the current log levels are pretty old. update the current list to
extend current default default_log_level defined in oslo-incubator
and adding in stevedore and keystoneclient levels

that is needed in stable/icehouse to allow swift+ceilometer
in devstack and devstack gate (otherwise grenade job, that is
using stable/icehouse devstack, won't pass the gate)

Change-Id: I239645ef641613a994a48f20c0238e76dc9660f2
Partial-Bug: #1294789
(cherry picked from commit 4d864ce)

ceilometer/service.py

@@ -93,6 +93,8 @@
 ]
 cfg.CONF.register_cli_opts(CLI_OPTIONS, group="service_credentials")
 
+cfg.CONF.import_opt('default_log_levels',
+                    'ceilometer.openstack.common.log')
 
 LOG = log.getLogger(__name__)
 
@@ -135,15 +137,10 @@ def prepare_service(argv=None):
     gettextutils.install('ceilometer', lazy=True)
     gettextutils.enable_lazy()
     rpc.set_defaults(control_exchange='ceilometer')
+    log_levels = (cfg.CONF.default_log_levels +
+                  ['stevedore=INFO', 'keystoneclient=INFO'])
     cfg.set_defaults(log.log_opts,
-                     default_log_levels=['amqplib=WARN',
-                                         'qpid.messaging=INFO',
-                                         'sqlalchemy=WARN',
-                                         'keystoneclient=INFO',
-                                         'stevedore=INFO',
-                                         'eventlet.wsgi.server=WARN',
-                                         'iso8601=WARN'
-                                         ])
+                     default_log_levels=log_levels)
     if argv is None:
         argv = sys.argv
     cfg.CONF(argv[1:], project='ceilometer')