fix cascade delete for user_prefs foreign keys and PG

schema/ttrss_schema_pgsql.sql

@@ -181,8 +181,8 @@ insert into ttrss_prefs (pref_name,type_id,def_value,short_desc,section_id,help_
 insert into ttrss_prefs (pref_name,type_id,def_value,short_desc,section_id) values('ENABLE_FEED_CATS', 1, 'false', 'Enable feed categories',2);
 
 create table ttrss_user_prefs (
-	owner_uid integer not null references ttrss_users(id) on delete cascade,
-	pref_name varchar(250) not null references ttrss_prefs(pref_name),
+	owner_uid integer not null references ttrss_users(id) ON DELETE CASCADE,
+	pref_name varchar(250) not null references ttrss_prefs(pref_name) ON DELETE CASCADE,
 	value text not null);
 
 create index ttrss_user_prefs_owner_uid_index on ttrss_user_prefs(owner_uid);