Escape anpersand when searching in Elasticsearch
diff --git a/ext/elasticsearch/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/ElasticsearchAnySearchDAO.java b/ext/elasticsearch/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/ElasticsearchAnySearchDAO.java
index e44cce2..8111a60 100644
--- a/ext/elasticsearch/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/ElasticsearchAnySearchDAO.java
+++ b/ext/elasticsearch/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/ElasticsearchAnySearchDAO.java
@@ -84,7 +84,7 @@
     protected static final QueryBuilder MATCH_ALL_QUERY_BUILDER = new MatchAllQueryBuilder();
 
     protected static final char[] ELASTICSEARCH_REGEX_CHARS = new char[] {
-        '.', '?', '+', '*', '|', '{', '}', '[', ']', '(', ')', '"', '\\' };
+        '.', '?', '+', '*', '|', '{', '}', '[', ']', '(', ')', '"', '\\', '&' };
 
     protected static String escapeForLikeRegex(final char c) {
         StringBuilder output = new StringBuilder();