create /var/log/cluster dir for corosync.conf during corosync
installation

using it in corosync 2
fix possible race
improve logging
don't set arch to null, if it is unknown

fixes:
java.lang.NullPointerException
null
lcmc.gui.dialog.host.HeartbeatInst.installHeartbeat(HeartbeatInst.java:95)
lcmc.gui.dialog.host.HeartbeatInst.initDialogAfterVisible(HeartbeatInst.java:85)
lcmc.gui.dialog.ConfigDialog.showDialog(ConfigDialog.java:574)
lcmc.AddHostDialog.showDialogs(AddHostDialog.java:62)
lcmc.gui.EmptyViewPanel$1$1.run(EmptyViewPanel.java:117)
java.lang.Thread.run(Unknown Source)
adjust junit tests