Ignore MultipartInvariantViolationDefect for message body if only considering the headers

Author: htsedebenham

Lib/email/feedparser.py

@@ -189,7 +189,7 @@ def close(self):
         assert not self._msgstack
         # Look for final set of defects
         if root.get_content_maintype() == 'multipart' \
-               and not root.is_multipart():
+               and not root.is_multipart() and not self._headersonly:
             defect = errors.MultipartInvariantViolationDefect()
             self.policy.handle_defect(root, defect)
         return root