Added code to make st-archive handle DART files

Author: kdraeder

cime_config/config_archive.xml

@@ -4,6 +4,7 @@
     <rest_file_extension>r</rest_file_extension>
     <rest_file_extension>rh\d*</rest_file_extension>
     <hist_file_extension>h\d*.*\.nc$</hist_file_extension>
+    <hist_file_extension>e</hist_file_extension>
     <rest_history_varname>locfnh</rest_history_varname>
     <rpointer>
       <rpointer_file>rpointer.rof$NINST_STRING</rpointer_file>