Rename open_id_authentication_tables migration to avoid clash

If there's another migration on master before this gets merged this'll
probably have to be changed again.

diff --git a/db/migrate/050_add_open_id_authentication_tables.rb b/db/migrate/052_add_open_id_authentication_tables.rb
similarity index 100%
rename from db/migrate/050_add_open_id_authentication_tables.rb
rename to db/migrate/052_add_open_id_authentication_tables.rb