Clear message cache table when upgrading

SQL/mysql.update.sql

@@ -131,3 +131,5 @@ ALTER TABLE `users` ADD UNIQUE `username` (`username`, `mail_host`);
 
 ALTER TABLE `contacts` MODIFY `email` varchar(255) NOT NULL;
 
+TRUNCATE TABLE `messages`;
+

SQL/postgres.update.sql

@@ -88,3 +88,4 @@ DROP INDEX users_username_id_idx;
 ALTER TABLE users ADD UNIQUE (username, mail_host);
 ALTER TABLE contacts ALTER email TYPE varchar(255);
 
+TRUNCATE messages;

SQL/sqlite.update.sql

@@ -180,3 +180,5 @@ INSERT INTO contacts (contact_id, user_id, changed, del, name, email, firstname,
 CREATE INDEX ix_contacts_user_id ON contacts(user_id, email);
 DROP TABLE contacts_tmp;
 
+DELETE FROM messages;
+