Remove unnnecessary code

Author: bhapas

modules/ingest-common/src/main/java/org/elasticsearch/ingest/common/CefParser.java

@@ -406,10 +406,6 @@ private static Map<String, String> parseExtensions(String extensionString) {
         while (matcher.find()) {
             String key = matcher.group(1);
             String value = matcher.group(2);
-            // Convert extension field name to strict legal field_reference
-            if (key.endsWith("]")) {
-                key = convertArrayLikeKey(key);
-            }
             extensions.put(key, desanitizeExtensionVal(value.trim()));
             lastEnd = matcher.end();
         }
@@ -517,14 +513,6 @@ private static void removeEmptyValues(Map<String, String> map) {
         map.values().removeIf(Strings::isEmpty);
     }
 
-    private static String convertArrayLikeKey(String key) {
-        Matcher matcher = EXTENSION_KEY_ARRAY_CAPTURE.matcher(key);
-        if (matcher.matches()) {
-            return "[" + matcher.group(1) + "]" + matcher.group(2);
-        }
-        return key;
-    }
-
     private static String desanitizeExtensionVal(String value) {
         String desanitized = value;
         for (Map.Entry<String, String> entry : EXTENSION_VALUE_SANITIZER_REVERSE_MAPPING.entrySet()) {