Fix the issue with schedule backup of internal DB 

that failed due to calling LogFile.verify_log_depot_settings that has been removed in https://github.com/ManageIQ/manageiq/pull/908.

https://bugzilla.redhat.com/show_bug.cgi?id=1173213
@brandondunne _("<english message text>") is the correct way to call our gettext support.  Dictionary lookup is for model, field, etc names, so not sure how that applies here.