mod_sasl2_bind2, mod_sasl2_sm: Remove bind2 <features/> wrapper element
This was dropped from the spec. It's more consistent with SASL2.
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summary: Remote Roster Management
...
Introduction
============
This module adds support for [XEP-0321: Remote Roster Management] which
is commonly used to allow components such as transports to modify the
rosters of local users.