User can't sort on fields like progress and sub tasks in issue navigator.

Steps:
1. Restore the attached data.
2. Login as veenu/pass. Search for all issues in project Dashboard.
3. Edit the columns by choosing Tools->Configure Columns and add fields like progress and sub tasks.
4. Go to View issue mode and try to sort on progress/sub tasks.

Result:
1. Nothing happens.
2. Its working fine in 3.13.5

Expected:
1. User should be able to sort on these fields.