Update travis excludes for 2.4.6
Update travis excludes for 2.4.6

missed in #5572,

we explicitly exclude all non-ruby jobs on the newer ruby version
(no point in running javascript specs twice)

so, updating the excluded ruby version to match the new one we're using

(Drops the number of travis jobs from 8 back to 5.)

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