Fixed possible overflow occurring in challenge hash key generation in MsnChallengeHandler.cpp
Fixed possible overflow occurring in challenge hash key generation in MsnChallengeHandler.cpp

svn path=/branches/work/kopete/msnp11_porting/; revision=433152

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