Re-generate library using /synth.py (googleapis#255)

Author: dpebot

handwritten/bigtable/src/v2/bigtable_client_config.json

@@ -17,13 +17,22 @@
           "rpc_timeout_multiplier": 1.0,
           "max_rpc_timeout_millis": 20000,
           "total_timeout_millis": 600000
+        },
+        "streaming": {
+          "initial_retry_delay_millis": 100,
+          "retry_delay_multiplier": 1.3,
+          "max_retry_delay_millis": 60000,
+          "initial_rpc_timeout_millis": 20000,
+          "rpc_timeout_multiplier": 1.0,
+          "max_rpc_timeout_millis": 20000,
+          "total_timeout_millis": 3600000
         }
       },
       "methods": {
         "ReadRows": {
-          "timeout_millis": 60000,
-          "retry_codes_name": "non_idempotent",
-          "retry_params_name": "default"
+          "timeout_millis": 3600000,
+          "retry_codes_name": "idempotent",
+          "retry_params_name": "streaming"
         },
         "SampleRowKeys": {
           "timeout_millis": 60000,