Fix a crash when someone changes nicks and someone else switches to their old nick (IRC).
Fix a crash when someone changes nicks and someone else switches to their
old nick (IRC).

CCMAIL: kopete-devel@kde.org

svn path=/trunk/kdenetwork/kopete/; revision=264986

josh-wambua/kopete,Jtalk/kopete-fork-xep0136,josh-wambua/kopete,Jtalk/kopete-fork-xep0136,josh-wambua/kopete,Jtalk/kopete-fork-xep0136,josh-wambua/kopete,Jtalk/kopete-fork-xep0136,josh-wambua/kopete,Jtalk/kopete-fork-xep0136,josh-wambua/kopete,Jtalk/kopete-fork-xep0136,josh-wambua/kopete