enh(BE): get the prepare statement out of the while clause

www/install/php/Update-19.04.5.php

@@ -64,16 +64,17 @@
 // correct the DN of manually imported users from an LDAP
 try {
     // finding the data of contacts linked to an LDAP
-    $stmt = $this->pearDB->query(
+    $stmt = $pearDB->query(
         "SELECT contact_id, contact_name, contact_ldap_dn FROM contact WHERE ar_id is NOT NULL"
     );
+    $updateDB = $pearDB->prepare(
+        "UPDATE contact SET contact_ldap_dn = :newDn WHERE contact_id = :contactId"
+    );
     while ($row = $stmt->fetch(\PDO::FETCH_ASSOC)) {
         // removing the double slashes if needed and saving the corrected data
         if (strpos($row['contact_ldap_dn'], "\\\\")) {
             $newDn = str_replace("\\\\", "\\", $row['contact_ldap_dn']);
-            $updateDB = $this->pearDB->prepare(
-                "UPDATE contact SET contact_ldap_dn = :newDn WHERE contact_id = :contactId"
-            );
+
             $updateDB->bindValue(':newDn', $newDn, \PDO::PARAM_STR);
             $updateDB->bindValue(':contactId', $row['contact_id'], \PDO::PARAM_INT);
             $updateDB->execute();