66-67 Data migration is broken

[joetsoi]

067_turn_extras_to_strings.py is currently broken due to 7677d69e , this is an example from a dump of pdeu before the change, after the change and what query should be executing.

pdeu=# select count(id) from package_extra  where left(value,1) = '"';
 count  
--------
 274194
(1 row)

pdeu=# select count(id) from package_extra  where substr(value,0,1) = '"';
 count 
-------
     0
(1 row)

pdeu=# select count(id) from package_extra  where substr(value,1,1) = '"';
 count  
--------
 274194
(1 row)

substr counts from 1, see examples in postgres docs