xmppthread: fix photo url format

The photo url must be https now.  Also process an error otherwise the
thread will crash.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

xmppthread.py

diff --git a/xmppthread.py b/xmppthread.py
index 4edd3dd..9853c36 100644
--- a/xmppthread.py
+++ b/xmppthread.py
@@ -192,7 +192,10 @@
         vcard['NICKNAME'] = user.full_name
         if user.photo_url:
             vcard['PHOTO']['TYPE'] = 'image/jpeg'
-            vcard['PHOTO']['BINVAL'] = urllib.request.urlopen('http:' + user.photo_url).read()
+            try:
+                vcard['PHOTO']['BINVAL'] = urllib.request.urlopen('https:' + user.photo_url).read()
+            except (urllib.error.HTTPError):
+                logging.info("Failed to load photo from %s", user.photo_url)
 
         self['xep_0054'].publish_vcard(jid=jid, vcard=vcard)