Use the gitlabhq fork of the MySQL converter

doc/update/mysql_to_postgresql.md

@@ -15,7 +15,7 @@ sudo service gitlab stop
 # Update /home/git/gitlab/config/database.yml
-git clone https://github.com/lanyrd/mysql-postgresql-converter.git
+git clone https://github.com/gitlabhq/mysql-postgresql-converter.git
 cd mysql-postgresql-converter
 mysqldump --compatible=postgresql --default-character-set=utf8 -r databasename.mysql -u root gitlabhq_production
 python db_converter.py databasename.mysql databasename.psql