Remove double Default option in Display Settings
Remove double Default option in Display Settings

fixing https://bugzilla.redhat.com/show_bug.cgi?id=1383308

Remove displaying double Default option under Display Settings section
when changing Chart Theme in My Settings -> Visual.
(transferred from ManageIQ/manageiq@f1f822d1350d8a2a7b82d1ca7403e324b31c9ad3)

ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic