Catch socket errors when closing SMTP connections.

doc/changelog.txt

@@ -8,6 +8,8 @@ Fixes:
 - gui: Fix sorting of columns in URL result list.
 - checking: Fix wrong __init__ call to URL proxy handler.
   Closes: SF bug #3118254
+- checking: Catch socket errors (for example socket.timeout)
+  when closing SMTP connections.
 
 Changes:
 - dependencies: Require and use Python 2.6.

linkcheck/checker/mailtourl.py

@@ -22,6 +22,7 @@ import re
 import urllib
 import urlparse
 import smtplib
+import socket
 from email._parseaddr import AddressList
 import sys
 
@@ -357,10 +358,12 @@ class MailtoUrl (urlbase.UrlBase):
             return
         connection = self.url_connection
         self.url_connection = None
+        raise
         try:
             connection.quit()
-        except smtplib.SMTPException:
+        except (smtplib.SMTPException, socket.error):
             # ignore close errors
+            # socket.error is raised for example on timeouts
             pass
 
     def set_cache_keys (self):