Update buildnml now that PLUMBER2SITE xmlchange is working

Author: TeaganKing

datm/cime_config/buildnml

@@ -148,7 +148,7 @@ def _create_namelists(case, confdir, inst_string, infile, nmlgen, data_list_path
                 # download and use the listing.csv file to determine data availablity
                 available_neon_data = _get_neon_data_availability(case, neonsite)
         if 'PLUMBER2' in clm_usrdat_name:
-            plumber2site = case.get_value('CASEROOT').split('/')[-1]
+            plumber2site = case.get_value('PLUMBER2SITE')
             if plumber2site:
                 config['plumber'] = "True"
     else: