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/
##############################################################################
# General Options
option('doc', type : 'boolean', value : false,
description : 'build documentation with gtk-doc')
option('extraversion', type : 'string',
description : 'extra version number to be displayed in Help->About and --help (for packagers)')
option('introspection', type : 'boolean', value : true,
description : 'build introspection data')
option('nettle', type : 'feature',
description : 'enable Nettle support')
option('nls', type : 'boolean', value : true,
description : 'enable installation of translation files')
option('pixmaps-install', type : 'boolean', value : true,
description : 'enable installation of pixmap files - Pidgin still needs them!')
##############################################################################
# Libpurple Options
option('farstream', type : 'feature',
description : 'compile with farstream support')
option('gstreamer-video', type : 'feature',
description : 'compile with GStreamer 1.0 Video Overlay support')
option('kwallet', type : 'feature',
description : 'enable KWallet support')
option('plugins', type : 'boolean', value : true,
description : 'compile plugins')
option('secret-service', type : 'feature',
description : 'enable Secret Service support')
option('vv', type : 'feature',
description : 'compile with voice and video support')
##############################################################################
# Protocol Plugins
option('avahi', type : 'feature',
description : 'compile with avahi (required for Bonjour support)')
option('cyrus-sasl', type : 'feature',
description : 'enable Cyrus SASL support for XMPP/IRC')
option('dynamic-prpls', type : 'string', value: 'all',
description : 'specify which protocols to build dynamically')
option('krb4', type : 'boolean', value : false,
description : 'compile Zephyr plugin with Kerberos 4 support')
option('libgadu', type : 'feature',
description : 'compile with libgadu (required for GaduGadu support)')
option('meanwhile', type : 'feature',
description : 'compile with meanwhile')
option('silc', type : 'feature',
description : 'compile with SILC plugin')
option('zephyr', type : 'feature',
description : 'compile Zephyr plugin against external libzephyr')
##############################################################################
# Pidgin Options
option('console-logging', type : 'boolean', value : false,
description : 'compile with console logging support')
option('gtkui', type : 'boolean', value : true,
description : 'compile with GTK+ user interface')
option('unity-integration', type : 'feature',
description : 'compile with support for unity integration plugin')
##############################################################################
# Finch Options
option('consoleui', type : 'boolean', value : true,
description : 'compile with console user interface')
option('x', type : 'boolean', value : true)