SDDP: use correct output port when setting DATA_TIME_STEP.
For algorithms that didn't setup DATA_TIME_STEP in RequestData
,
vtkStreamingDemandDrivenPipeline has logic to copy the UPDATE_TIME_STEP
from output port to the data info. For multi output port algorithms,
vtkStreamingDemandDrivenPipeline should be copying UPDATE_TIME_STEP from
the port the update request is coming from since that's the one that has
the correct time step. Fixed that.