Quit SMTP connection on any initialization failure

Broaden the except clause from SMTPAuthenticationError to Exception
so the connection is cleaned up when starttls() or
ehlo_or_helo_if_needed() fails as well.

Fixes #179

Author: lavr

emails/backend/smtp/client.py

@@ -27,7 +27,7 @@ def __init__(self, parent, **kwargs):
 
         try:
             self.initialize()
-        except smtplib.SMTPAuthenticationError:
+        except Exception:
             self.quit()
             raise