pidgin/pidgin

Fix a crash on shutdown in kwallet if the wallet was never opened.

The wallet instance variable was not initialized so if the wallet was never opened we were trying to delete and invalid pointer.

Also update the dispose method of the provider to close the wallet as the
tasks in the queue hold a reference to the provider instance as the source
object in their tasks.

Testing Done:
Ran locally with both the kwallet and secret service providers.

Reviewed at https://reviews.imfreedom.org/r/581/
<?xml version="1.0" encoding="UTF-8"?>
<!-- Copyright 2014 Richard Hughes <richard@hughsie.com> -->
<!-- Copyright 2014-2017 Pidgin Developers <devel@pidgin.im> -->
<component type="desktop-application">
<id>im.pidgin.Pidgin3.desktop</id>
<metadata_license>CC0-1.0</metadata_license>
<project_license>GPL-2.0</project_license>
<description>
<p>
Pidgin is a chat program which lets you log in to accounts on multiple
chat networks simultaneously.
</p>
<p>
This means that you can be chatting with friends on AIM, talking to a
friend on Google Talk, and sitting in an IRC chat room all at the same
time.
</p>
</description>
<launchable type="desktop-id">im.pidgin.Pidgin3.desktop</launchable>
<provides>
<id>pidgin3.desktop</id>
</provides>
<screenshots>
<screenshot type="default">
<image>https://old.pidgin.im/shared/img/contact_window.png</image>
<caption>Buddy list showing friends on different networks</caption>
</screenshot>
</screenshots>
<url type="homepage">https://pidgin.im/</url>
<url type="bugtracker">https://developer.pidgin.im/timeline</url>
<url type="faq">https://developer.pidgin.im/wiki/FAQ</url>
<url type="help">https://developer.pidgin.im/wiki</url>
<update_contact>devel@pidgin.im</update_contact>
</component>