Fix a division by zero bug

Thanks to Sickness for reporting this and providing backtraces and for flakes
for writing a first patch that Sickness tested.


git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@1603 726aef4b-f618-498e-8847-2d620e286838

User.cpp

@@ -704,6 +704,10 @@ CChan* CUser::FindChan(const CString& sName) const {
 }
 
 void CUser::JoinChans() {
+	// Avoid divsion by zero, it's bad!
+	if (m_vChans.size() == 0)
+		return;
+
 	// We start at a random offset into the channel list so that if your
 	// first 3 channels are invite-only and you got MaxJoins == 3, ZNC will
 	// still be able to join the rest of your channels.