Fix incorrect logger invocation

It looks like auto-complete gave us a nasty surprise here with
Logger#equals being invoked instead of Logger#error swallowing the
absolute worst-possible level of a log message. This commit fixes the
invocation.

modules/transport-netty4/src/main/java/org/elasticsearch/transport/netty4/Netty4InternalESLogger.java

@@ -161,7 +161,7 @@ class Netty4InternalESLogger extends AbstractInternalLogger {
 
     @Override
     public void error(String msg) {
-        logger.equals(msg);
+        logger.error(msg);
     }
 
     @Override