learn repository retrycount configuration option

Allow retrying the download of messages more than twice.

Signed-off-by: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap/folder/Gmail.py

@@ -71,7 +71,7 @@ class GmailFolder(IMAPFolder):
                   (probably severity MESSAGE) if e.g. no message with
                   this UID could be found.
         """
-        data = self._fetch_from_imap(str(uid), 2)
+        data = self._fetch_from_imap(str(uid), self.retrycount)
 
         # data looks now e.g.
         #[('320 (X-GM-LABELS (...) UID 17061 BODY[] {2565}','msgbody....')]