Adjust BWC version on client features

This commit adjusts the BWC version on client features in 6.x to 6.3.0
after the functionality was backported to the 6.3 branch.

Author: jasontedor

modules/transport-netty4/src/main/java/org/elasticsearch/transport/netty4/ESLoggingHandler.java

@@ -105,7 +105,7 @@ else if (readableBytes >= TcpHeader.HEADER_SIZE) {
                                 context.readHeaders(in);
                             }
                             // now we decode the features
-                            if (in.getVersion().onOrAfter(Version.V_6_4_0)) {
+                            if (in.getVersion().onOrAfter(Version.V_6_3_0)) {
                                 in.readStringArray();
                             }
                             // now we can decode the action name

server/src/main/java/org/elasticsearch/transport/TcpTransport.java

@@ -1112,7 +1112,7 @@ private void sendRequestToChannel(final DiscoveryNode node, final TcpChannel cha
 
             stream.setVersion(version);
             threadPool.getThreadContext().writeTo(stream);
-            if (version.onOrAfter(Version.V_6_4_0)) {
+            if (version.onOrAfter(Version.V_6_3_0)) {
                 stream.writeStringArray(features);
             }
             stream.writeString(action);
@@ -1519,7 +1519,7 @@ protected String handleRequest(TcpChannel channel, String profileName, final Str
                                    int messageLengthBytes, Version version, InetSocketAddress remoteAddress, byte status)
         throws IOException {
         final Set<String> features;
-        if (version.onOrAfter(Version.V_6_4_0)) {
+        if (version.onOrAfter(Version.V_6_3_0)) {
             features = Collections.unmodifiableSet(new TreeSet<>(Arrays.asList(stream.readStringArray())));
         } else {
             features = Collections.emptySet();