Remove unused constant

Author: bhapas

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

@@ -60,7 +60,6 @@ final class CefParser {
 
     // New patterns for extension parsing
     private static final String EXTENSION_KEY_PATTERN = "(?:[\\w-]+(?:\\.[^\\.=\\s\\|\\\\\\[\\]]+)*(?:\\[[0-9]+\\])?(?==))";
-    private static final Pattern EXTENSION_KEY_ARRAY_CAPTURE = Pattern.compile("^([^\\[\\]]+)((?:\\[[0-9]+\\])+)$");
     private static final String EXTENSION_VALUE_PATTERN = "(?:[^\\s\\\\]|\\\\[^|]|\\s(?!" + EXTENSION_KEY_PATTERN + "=))*";
     private static final Pattern EXTENSION_NEXT_KEY_VALUE_PATTERN = Pattern.compile(
         "(" + EXTENSION_KEY_PATTERN + ")=(" + EXTENSION_VALUE_PATTERN + ")(?:\\s+|$)"