Steps to reproduce:

1. Create a LDAP user name with mix case or Capital case in JIRA 4.4.1, let's say 'ABC' in this case
2. Use this username 'ABC' to create certain dashboard in JIRA 4.4.1
3. Check in 4.4.1 database by running:

   select * from favouriteassociations;
   

   it will show the sequence of the user dashboard as showing below:
   

4. Export the database from JIRA 4.4.1, let's say 'test.xml'
5. Import the 'test.xml' into JIRA5.1.6
6. Login as user 'ABC' and the dashboard sequence will be changed.
7. Check in 5.1.6 database by running:

   select * from favouriteassociations;
   

   it will show the sequence of the user dashboard as showing below:
   

From here we can see the sequence all become the same number '4' and the username automatically become to small letters as 'abc' instead of 'ABC'.