tools: fix handling of config/template errors

This is a follow-up of the Python 3 port.
The `message` field is no longer supported in standard exceptions.

mkexp

@@ -81,7 +81,7 @@ def expand_template(template_dict, template_names):
     try:
         return template_env.select_template(template_names).render(template_dict)
     except TemplatesNotFound as error:
-        feedback.die(error.message)
+        feedback.die(error)
 
 def expand_template_file(template_dict, template_names, expanded_name,
     backup_name, executable):
@@ -92,7 +92,7 @@ def expand_template_file(template_dict, template_names, expanded_name,
         for line in template_env.select_template(template_names).generate(template_dict):
             expanded_file.write(line)
     except TemplatesNotFound as error:
-        feedback.die(error.message)
+        feedback.die(error)
     expanded_file.write(u'\n')
     expanded_file.close()
     if executable:
@@ -416,7 +416,7 @@ try:
     config = ExpConfig(experiment_config_name, extra_dict, config_roots,
                        getexp=args.getexp)
 except ExpConfigError as error:
-    feedback.die(str(error), status=2)
+    feedback.die(error, status=2)
 
 # Create target directories
 

selconfig

@@ -47,7 +47,7 @@ try:
         config_file = sys.stdin
     config_data = ConfigObj(config_file, file_error=True)
 except IOError as error:
-    die(error.message)
+    die(error)
 
 # Walk config to the appropriate section and create output structure
 

setconfig

@@ -61,7 +61,7 @@ try:
             add_file = sys.stdin
         config_data.merge(ConfigObj(add_file, file_error=True))
 except IOError as error:
-    die(error.message)
+    die(message)
 
 # Remove keys from --delete command line option