Add support for failover instances. (#1810)

This PR was generated using Autosynth. 🌈

Here's the log from Synthtool:
```
synthtool > Executing /tmpfs/src/git/autosynth/working_repo/Redis/synth.py.
synthtool > Ensuring dependencies.
synthtool > Pulling artman image.
latest: Pulling from googleapis/artman
Digest: sha256:d9597f983d1d4e61272c63cb97b7d8f8234da9999526c35d357de3d781f0ec1b
Status: Image is up to date for googleapis/artman:latest
synthtool > Cloning googleapis.
synthtool > Running generator for google/cloud/redis/artman_redis_v1beta1.yaml.
synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/php/google-cloud-redis-v1beta1.
synthtool > Running generator for google/cloud/redis/artman_redis_v1.yaml.
synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/php/google-cloud-redis-v1.
synthtool > Replaced 'Copyright \\d{4}' in src/V1/Gapic/CloudRedisGapicClient.php.
synthtool > Replaced 'Copyright \\d{4}' in src/V1beta1/Gapic/CloudRedisGapicClient.php.
synthtool > Replaced 'Copyright \\d{4}' in tests/Unit/V1/CloudRedisClientTest.php.
synthtool > Replaced 'Copyright \\d{4}' in tests/Unit/V1/CloudRedisClientPartialVeneerTest.php.
synthtool > Replaced 'Copyright \\d{4}' in tests/Unit/V1beta1/CloudRedisClientTest.php.
synthtool > Replaced 'Copyright \\d{4}' in tests/Unit/V1beta1/CloudRedisClientPartialVeneerTest.php.
synthtool > Replaced 'Copyright \\d{4}' in tests/System/V1/CloudRedisClientTest.php.
synthtool > Replaced 'Copyright \\d{4}' in tests/System/V1beta1/CloudRedisClientTest.php.
synthtool > Replaced 'will be removed in the next major release' in src/V1/FailoverInstanceRequest_DataProtectionMode.php.
synthtool > Replaced 'will be removed in the next major release' in src/V1/Instance_State.php.
synthtool > Replaced 'will be removed in the next major release' in src/V1/Instance_Tier.php.
synthtool > Replaced 'will be removed in the next major release' in src/V1beta1/FailoverInstanceRequest_DataProtectionMode.php.
synthtool > Replaced 'will be removed in the next major release' in src/V1beta1/Instance_State.php.
synthtool > Replaced 'will be removed in the next major release' in src/V1beta1/Instance_Tier.php.
synthtool > Replaced 'Instance_Tier' in src/V1/Gapic/CloudRedisGapicClient.php.
synthtool > Replaced 'Instance_Tier' in src/V1beta1/Gapic/CloudRedisGapicClient.php.
synthtool > Cleaned up 1 temporary directories.
synthtool > Wrote metadata to synth.metadata.

```

Redis/src/V1beta1/CloudRedisGrpcClient.php

@@ -2,7 +2,7 @@
 // GENERATED CODE -- DO NOT EDIT!
 
 // Original file comments:
-// Copyright 2018 Google Inc.
+// Copyright 2019 Google LLC.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //
+//
 namespace Google\Cloud\Redis\V1beta1;
 
 /**
@@ -84,7 +85,7 @@ public function GetInstance(\Google\Cloud\Redis\V1beta1\GetInstanceRequest $argu
     /**
      * Creates a Redis instance based on the specified tier and memory size.
      *
-     * By default, the instance is peered to the project's
+     * By default, the instance is accessible from the project's
      * [default network](/compute/docs/networks-and-firewalls#networks).
      *
      * The creation is executed asynchronously and callers may check the returned
@@ -124,6 +125,21 @@ public function UpdateInstance(\Google\Cloud\Redis\V1beta1\UpdateInstanceRequest
         $metadata, $options);
     }
 
+    /**
+     * Failover the master role to current replica node against a specific
+     * STANDARD tier redis instance.
+     * @param \Google\Cloud\Redis\V1beta1\FailoverInstanceRequest $argument input argument
+     * @param array $metadata metadata
+     * @param array $options call options
+     */
+    public function FailoverInstance(\Google\Cloud\Redis\V1beta1\FailoverInstanceRequest $argument,
+      $metadata = [], $options = []) {
+        return $this->_simpleRequest('/google.cloud.redis.v1beta1.CloudRedis/FailoverInstance',
+        $argument,
+        ['\Google\LongRunning\Operation', 'decode'],
+        $metadata, $options);
+    }
+
     /**
      * Deletes a specific Redis instance.  Instance stops serving and data is
      * deleted.