rally handler: use ScheduleHandlerBase as parent class
rally handler: use ScheduleHandlerBase as parent class

RedHat-Eng-PGM/python-schedules-tools,RedHat-Eng-PGM/python-schedules-tools,RedHat-Eng-PGM/schedules-tools,RedHat-Eng-PGM/python-schedules-tools,RedHat-Eng-PGM/schedules-tools,RedHat-Eng-PGM/schedules-tools