Security update for python3-sleekxmpp

This update for python3-sleekxmpp fixes the following issues:

- Check the origin of roster pushes (2015-8688, 2016-9928, boo#1014976). Also
see https://gultsch.de/gajim_roster_push_and_message_interception.html
- An error in legacyauth support was fixed

Fixed bugs
bnc#1014976
VUL-1: CVE-2016-9928: MCabber: remote attackers can modify the roster and intercept messages via a crafted roster-push IQ stanza
Selected Binaries
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