Fix typo in true/false check

lofar-cwl/steps/LoSoTo.Plot.cwl

@@ -26,7 +26,7 @@ requirements:
 
           INPUT_H5PARM=$(inputs.input_h5parm.basename)
           DO_PLOTS=$(inputs.execute)
-          if [ "$DO_PLOT" = "true" ]; then
+          if [ "$DO_PLOTS" = "true" ]; then
             losoto --verbose $INPUT_H5PARM parset.config
           else
             echo Skipped plotting 3rd order tec solutions