Fix incorrect creation dates for e3sm_to_cmip maps

Compass was prepending `20` to the creation date but our creation
dates already include the full 4-digit year.

compass/ocean/tests/global_ocean/files_for_e3sm/e3sm_to_cmip_maps.py

@@ -49,8 +49,7 @@ def run(self):
         Run this step of the testcase
         """
         super().run()
-        # more verbose creation date for clarity
-        creation_date = f'20{self.creation_date}'
+        creation_date = self.creation_date
         make_e3sm_to_cmip_maps(self.config, self.logger, self.mesh_short_name,
                                creation_date, self.ntasks)