fixed GetReplicaSetConfig to use the proper name 'setVersion' instead of 'version'.

Author: craiggwilson

src/MongoDB.Driver.Core.Tests/Core/Connections/IsMasterResultTests.cs

@@ -201,7 +201,7 @@ public void GetReplicaSetConfig_should_return_correct_info_when_the_server_is_a_
                 { "hosts", new BsonArray(new [] { "localhost:1000", "localhost:1001" })},
                 { "passives", new BsonArray(new [] { "localhost:1002"}) },
                 { "arbiters", new BsonArray(new [] { "localhost:1003"}) },
-                { "version", 20 }
+                { "setVersion", 20 }
             };
 
             var subject = new IsMasterResult(doc);

src/MongoDB.Driver.Core/Core/Connections/IsMasterResult.cs

@@ -334,7 +334,7 @@ public ReplicaSetConfig GetReplicaSetConfig()
             var members = GetMembers();
             var name = (string)_wrapped.GetValue("setName", null);
             var primary = GetPrimary();
-            var version = _wrapped.Contains("version") ? (int?)_wrapped["version"].ToInt32() : null;
+            var version = _wrapped.Contains("setVersion") ? (int?)_wrapped["setVersion"].ToInt32() : null;
 
             return new ReplicaSetConfig(members, name, primary, version);
         }