JIRA WDT-34 Avoid including null loggers in list

Author: rakillen

core/src/main/java/oracle/weblogic/deploy/logging/PlatformLogger.java

@@ -542,7 +542,9 @@ public static List<Logger> getLoggers() {
         while (e.hasMoreElements()) {
             String loggerName = e.nextElement();
             Logger logger = manager.getLogger(loggerName);
-            topList.add(logger);
+            if(logger != null) {
+                topList.add(logger);
+            }
         }
         return topList;
     }