Update the data center models to avoid warnings

[mildwall]

When I ran the data center models in Buildings.Examples.ChillerPlant.DataCenterContinuousTimeControl and Buildings.Examples.ChillerPlant.DataCenterDiscreteTimeControl, I found several warnings:

dymosim started
... "dsin.txt" loading (dymosim input file)
Warning: The following was detected at time: 13046400
  *** Warning: You are using a flow or pressure controlled mover with the
             default pressure curve.
             This leads to approximate calculations of the electrical power
             consumption. Add the correct pressure curve in the record per
             to obtain an accurate computation.
             Setting nominalValuesDefineDefaultPressureCurve=true will suppress this warning
  Failed condition: fan.nominalValuesDefineDefaultPressureCurve

Warning: The following was detected at time: 13046400
  *** Warning: You are using a flow or pressure controlled mover with the
             default pressure curve.
             This leads to approximate calculations of the electrical power
             consumption. Add the correct pressure curve in the record per
             to obtain an accurate computation.
             Setting nominalValuesDefineDefaultPressureCurve=true will suppress this warning
  Failed condition: pumCHW.nominalValuesDefineDefaultPressureCurve

Warning: The following was detected at time: 13046400
  *** Warning: You are using a flow or pressure controlled mover with the
             default pressure curve.
             This leads to approximate calculations of the electrical power
             consumption. Add the correct pressure curve in the record per
             to obtain an accurate computation.
             Setting nominalValuesDefineDefaultPressureCurve=true will suppress this warning
  Failed condition: pumCW.nominalValuesDefineDefaultPressureCurve

The parameters fan.nominalValuesDefineDefaultPressureCurve, pumCHW.nominalValuesDefineDefaultPressureCurve and pumCW.nominalValuesDefineDefaultPressureCurve in both models should be changed to True to avoid warnings. Changing theses parameters would not affect the simulation results.

[mwetter]

@mildwall : This would be a good change. Can you please make a pull request.

[mildwall]

Thanks, I have made a pull request.