simplify error message in unique_ordered_append

Co-authored-by: Alexander Grund <[email protected]>

Author: lexming

easybuild/tools/utilities.py

@@ -231,8 +231,7 @@ def unique_ordered_append(base, extra):
     try:
         base.extend(extra)
     except TypeError as err:
-        err_msg = f"_unique_ordered_list_append: given extra list is not iterable: {extra}"
-        raise EasyBuildError(err_msg) from err
+        raise EasyBuildError( f"given extra list is not iterable: {extra}") from err
     except AttributeError as err:
         err_msg = f"_unique_ordered_list_append: given base cannot be extended: {base}"
         raise EasyBuildError(err_msg) from err