Usernames in Team Calendar's restrictions are not case insensitive

Same issue as reported in TEAMCAL-1219

Using Confluence 4.3.7 with Team Calendars 4.0.3

Created 2 usernames in LDAP, one with a capital and another all in lowercase. When restricting editing access to the user with a capital, they still cannot edit. Restricting editing access to the user all in lowercase, the user may edit.