pidgin/pidgin

Stop automatically adding/remove conversations from the conversation manager

This was done to mimic the old conversations API and shouldn't be needed going
forward. However, since we can't create conversations right now, we're probably
missing some edge cases here.

Also make sure to keep a reference around on the conversation while removing to avoid use after frees.

Testing Done:
Trained with the turtles.

Reviewed at https://reviews.imfreedom.org/r/3049/
Björn Voigt <bjoernv@arcor.de> Björn Voigt <bjoern@cs.tu-berlin.de>
Björn Voigt <bjoernv@arcor.de> Bjoern Voigt <bjoern@cs.tu-berlin.de>
David Woodhouse <dwmw2@infradead.org> <David.Woodhouse@intel.com>
David Woodhouse <dwmw2@infradead.org> <dwmw@amazon.co.uk>
David Woodhouse <dwmw2@infradead.org> dwmw2 <dwmw2@infradead.org>
# not sure how to make this one work because this doesn't do it..
dequis <dx@dxzone.com.ar> dequis <dx@dxzone.com.ar
dequis <dx@dxzone.com.ar> dx <dx@dxzone.com.ar>
Eion Robb <eion@robbmob.com> Eion Robb <eionrobb@gmail.com>
Elliott Sales de Andrade <quantum.analyst@gmail.com> Elliott Sales de Andrade <qulogic@pidgin.im>
Elliott Sales de Andrade <quantum.analyst@gmail.com> Elliott S <quantum.analyst@gmail.com>
Ethan Blanton <elb@pidgin.im> Ethan Blanton <elb@fiji-systems.com>
Ethan Blanton <elb@pidgin.im> Ethan Blanton <elb@kb8ojh.net>
Gary Kramlich <grim@reaperworld.com> <grim@pidgin.im>
Jerin Philip <monu1618@gmail.com> Jerin Philip <jerin.philip@students.iiit.ac.in>
Jonathan Champ <jrchamp@ncsu.edu> Jonathan Champ <royanee@users.sourceforge.net>
Jorge Villaseñor <salinasv@pidgin.im> Jorge Villaseñor <masca@cpw.pidgin.im>
Mark Doliner <mark@kingant.net> Mark Doliner <markdoliner@pidgin.im>
Matěj Cepl <mcepl@cepl.eu> Matěj Cepl <mcepl@redhat.com>
Michael McConville <mmcconville@mykolab.com> Michael McConville <mmcco@mykolab.com>
Michael McConville <mmcconville@mykolab.com> mmcconville@mykolab.com
Mike Ruprecht <cmaiku@gmail.com> Michael Ruprecht <maiku@pidgin.im>
Richard Laager <rlaager@wiktel.com> Richard Laager <rlaager@pidgin.im>
Robert Vehse <robertvehse@fastmail.fm> Robbie <robertvehse@fastmail.fm>
Shalom Craimer <scraimer@gmail.com> Shalom Craimer <s.transifex2015@craimer.org>
Tomasz Wasilczyk <twasilczyk@pidgin.im> Tomasz Wasilczyk <tomkiewicz@cpw.pidgin.im>
Yngve Spjeld Landro <l10n@landro.net> Yngve Spjeld Landro <nynorsk@strilen.net>