Fix config options for reference climatologies

The start and end year for reference climatologies were getting
overridden by the user's specified start and end year for normal
climatologies.

(This maybe suggests that we should consider a different
strategy for setting the start and end years and dates for
reference climatologies that doesn't rely on overriding the user
config options.)

mpas_analysis/shared/climatology/ref_year_mpas_climatology_task.py

@@ -100,10 +100,12 @@ def get_start_and_end(self):
         startDate = '{:04d}-01-01_00:00:00'.format(startYear)
         endDate = '{:04d}-12-31_23:59:59'.format(endYear)
 
-        config.set('climatology', 'startYear', str(startYear))
-        config.set('climatology', 'startDate', startDate)
-        config.set('climatology', 'endYear', str(endYear))
-        config.set('climatology', 'endDate', endDate)
+        # using "user=True" so these changes take priority over user config
+        # options
+        config.set('climatology', 'startYear', str(startYear), user=True)
+        config.set('climatology', 'startDate', startDate, user=True)
+        config.set('climatology', 'endYear', str(endYear), user=True)
+        config.set('climatology', 'endDate', endDate, user=True)
 
         return startYear, endYear