Make CClient::GetNickMask() always return a valid nickmask

The recent removal of CUser::m_bIRCConnected lead to a bug here which is now
fixed.
In addition to this, this function now also works properly for users without
a vhost.

Oh and in User.cpp: Make sure CUser::GetIRCServer() returns an empty string
when we are no longer connected to an IRCd.


git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@1134 726aef4b-f618-498e-8847-2d620e286838

User.cpp

@@ -119,6 +119,8 @@ void CUser::IRCDisconnected() {
 		m_vClients[a]->IRCDisconnected();
 	}
 
+	SetIRCServer("");
+
 	// Get the reconnect going
 	CZNC::Get().EnableConnectUser();
 }