add missing iso datastore icon
add missing iso datastore icon

https://bugzilla.redhat.com/show_bug.cgi?id=1331251

[skip ci]
(transferred from ManageIQ/manageiq@daa8a645d595c3bfe8953ed985f27879fe65ced2)

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