compliance: clarify CODEOWNER message

When find an entry in CODEOWNERS that is not the tree, make it clear in
the error message.

Signed-off-by: Anas Nashif <[email protected]>

Author: nashif

scripts/check_compliance.py

@@ -500,7 +500,7 @@ def ls_owned_files(self, codeowners):
                     files.append(str(abs_path.relative_to(top_path)))
 
                 if not files:
-                    self.add_failure("Path '{}' not found, in "
+                    self.add_failure("Path '{}' not found in the tree but is listed in "
                                      "CODEOWNERS".format(git_patrn))
 
                 pattern2files[git_patrn] = files