mirror_check: Increase connection timeout

The fastly test showed that the DNS was slow to resolve for some
people, sometimes exceeding 5 seconds.

Double the timeout value for the connection to work around that issue.

More info at linuxmint/linuxmint#658.

usr/lib/linuxmint/mintUpdate/mintUpdate.py

@@ -2019,7 +2019,7 @@ def get_url_last_modified(self, url):
         try:
             c = pycurl.Curl()
             c.setopt(pycurl.URL, url)
-            c.setopt(pycurl.CONNECTTIMEOUT, 5)
+            c.setopt(pycurl.CONNECTTIMEOUT, 10)
             c.setopt(pycurl.TIMEOUT, 30)
             c.setopt(pycurl.FOLLOWLOCATION, 1)
             c.setopt(pycurl.NOBODY, 1)