Changes calcuation of variable delay
Changes calcuation of variable delay

In the loopingcall.FixedIntervalLoopingCall class, an warning is logged
when 'delay' is equal or less than zero. Commonly delayed time is
considered something over due from a deadline which is a positive value.

Also a task delayed zero seconds is not considered delayed
but finished on time.

Therefore this patch fixes the calculation of the variable 'delay' and
omits a warning log when 'delay' is zero

Change-Id: I9dbae0838e6c03fa0eaa79e7332e650b02ed9c77

poznyakandrey/oslo.service,eezhova/oslo.service,openstack/oslo.service,citrix-openstack-build/oslo.service