Comment author not being upgraded correctly when using upper cases in LDAP user

Steps to Reproduce:

1. Create a user with upper case letters in a LDAP server (e.g. John)
2. Connect this LDAP server to a JIRA 5.X
3. Add a comment to any issue using the user created above
4. Upgrade JIRA to 6.x

Expected Results:
JIRA should display the comment author display name as was displayed on the previous version

Actual Results:
JIRA displays the actual user name, instead of the display name

Workaround
You can change the comment author to match the new casing with the following update in the database

update jiraaction
set author = lower(author)
where author not in (select lower_user_name from cwd_user)
and lower(author) in (select lower_user_name from cwd_user)

If this does not find any rows to update, you are using a case insensitive collation and will need to change that first.

Please remember to always have a database backup before doing changes directly to the database