Fix bug in the 'rename' command (Cmd-Line tool)

the 'rename' command only worked when the model to be renamed had an
evaluation history file created, which makes no sense. Users should be
able to rename their models anytime, regardless of whether your model
has been evaluated or not.

pyss3/cmd_line.py

@@ -1341,6 +1341,15 @@ def do_rename(self, args):
         """
         Rename the current model with a given name.
 
+        usage:
+            rename NEW_MODEL_NAME
+
+        required arguments:
+         NEW_MODEL_NAME      the model's new name
+        """
+                """
+        Rename the current model with a given name.
+
         usage:
             rename NEW_MODEL_NAME
 
@@ -1352,26 +1361,25 @@ def do_rename(self, args):
         if len(args) == 1:
             m_folder = CLF.__models_folder__
             m_name = CLF.__name__
+            m_ext = STR_MODEL_EXT
+            model_file = path.join(m_folder, "%s.%s" % (m_name, m_ext))
+            model_new_file = path.join(m_folder, "%s.%s" % (args[0], m_ext))
             rh_ext = RESULT_HISTORY_EXT
             rh_file = path.join(m_folder, m_name + rh_ext)
             rh_new_file = path.join(m_folder, args[0] + rh_ext)
 
             rename = True
-            if path.exists(rh_new_file):
+            if path.exists(model_new_file):
                 print()
                 Print.warn(WARN_OVERWRITE, False)
                 if input() != 'Y':
                     rename = False
 
             if rename:
-                rename_file(rh_file, rh_new_file)
-
-                m_ext = STR_MODEL_EXT
-                model_file = path.join(m_folder, "%s.%s" % (m_name, m_ext))
-                model_new_file = path.join(
-                    m_folder, "%s.%s" % (args[0], m_ext)
-                )
-                rename_file(model_file, model_new_file)
+                if path.exists(rh_file):
+                    rename_file(rh_file, rh_new_file)
+                if path.exists(model_file):
+                    rename_file(model_file, model_new_file)
                 CLF.__name__ = args[0]
         else:
             Print.error(ERROR_WAN % (1, len(args)))