Include clientImpl headers in java client RPC calls (#424)

Author: andrewjdawson2016

src/main/java/com/uber/cadence/serviceclient/WorkflowServiceTChannel.java

@@ -433,7 +433,8 @@ private static Map<String, String> getThriftHeaders(ClientOptions options) {
             .put("user-name", envUserName)
             .put("host-name", envHostname)
             .put("cadence-client-library-version", Version.LIBRARY_VERSION)
-            .put("cadence-client-feature-version", Version.FEATURE_VERSION);
+            .put("cadence-client-feature-version", Version.FEATURE_VERSION)
+            .put("cadence-client-name", "uber-java");
 
     if (options.headers != null) {
       for (Map.Entry<String, String> entry : options.headers.entrySet()) {