remove unnecessary null check

Author: deleonenriqueta

logback13/src/main/java/com/newrelic/logging/logback13/NewRelicAsyncAppender.java

@@ -62,9 +62,7 @@ protected void append(ILoggingEvent eventObject) {
         Map<String, String> copyMdc = MDC.getMDCAdapter().getCopyOfContextMap();
         if (copyMdc != null) {
             for (Map.Entry<String, String> entry : copyMdc.entrySet()) {
-                if (entry.getKey() != null && entry.getValue() != null) {
-                    combinedContextMap.put(CONTEXT_PREFIX + entry.getKey(), entry.getValue());
-                }
+                combinedContextMap.put(CONTEXT_PREFIX + entry.getKey(), entry.getValue());
             }
         }