update the UNSMRY file for the OPM reference solution

this one changed because the current master only writes at the end of
each report step instead of at the end of each time step plus at the
end of each report step as it used to be. the curves seem to be
identical when ajusting for this, i.e. they touch at what seems to be
the end of report step.

the reference data is now hosted in a folder with the generic name
'OPM-reference-simulation'.

update plotwells.sh accordingly

norne/plotwells.sh

@@ -5,7 +5,7 @@
 SUMMARY_X=summary.x
 
 OUTPUT=norne-wells
-DIRS="ECL.2014.2 OPM/2016.03.17"
+DIRS="ECL.2014.2 OPM/OPM-reference-simulation"
 DECK=NORNE_ATW2013
 
 # if empty all options will be plotted