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
@lfu @Fryguy What do you think of this idea? https://github.com/lfu/manageiq/pull/1