gmail: fix error when gmail.com is unreachable

ex: no internet connection

Signed-off-by: Adrian C. (anrxc) <anrxc@sysphere.org>

widgets/gmail.lua

@@ -44,6 +44,10 @@ local function worker(format, warg)
     -- Could be huge don't read it all at once, info we are after is at the top
     local xml = f:read(2000)
 
+    if xml ~= nil then
+        return mail
+    end
+
     mail["{count}"] = -- Count comes before messages and matches at least 0
       tonumber(string.match(xml, "<fullcount>([%d]+)</fullcount>")) or mail["{count}"]