Revert of Add field_specs to all metrics in luci-py

appengine/machine_provider/metrics.py

Index: appengine/machine_provider/metrics.py
diff --git a/appengine/machine_provider/metrics.py b/appengine/machine_provider/metrics.py
index 4620c8e00b635a895a93d2ad682d55650238b45f..13b8b7ad330ced156be88b8167b8a4148ea8e27c 100644
--- a/appengine/machine_provider/metrics.py
+++ b/appengine/machine_provider/metrics.py
@@ -9,29 +9,29 @@
 
 lease_requests_deduped = gae_ts_mon.CounterMetric(
     'machine_provider/lease_requests/deduped',
-    'Number of lease requests deduplicated.',
-    None)
+    description='Number of lease requests deduplicated.',
+)
 
 
 lease_requests_expired = gae_ts_mon.CounterMetric(
     'machine_provider/lease_requests/expired',
-    'Number of lease requests expired.',
-    None)
+    description='Number of lease requests expired.',
+)
 
 
 lease_requests_fulfilled = gae_ts_mon.CounterMetric(
     'machine_provider/lease_requests/fulfilled',
-    'Number of lease requests fulfilled.',
-    None)
+    description='Number of lease requests fulfilled.',
+)
 
 
 lease_requests_received = gae_ts_mon.CounterMetric(
     'machine_provider/lease_requests/received',
-    'Number of lease requests received.',
-    None)
+    description='Number of lease requests received.',
+)
 
 
 pubsub_messages_sent = gae_ts_mon.CounterMetric(
     'machine_provider/pubsub_messages/sent',
-    'Number of Pub/Sub messages sent.',
-    [gae_ts_mon.StringField('target')])
+    description='Number of Pub/Sub messages sent.',
+)