Change phpCAS log file path on cas.log

Because /tmp/ is not always the system one (=chrooted) and may be not writeable.

index.php

@@ -33,7 +33,7 @@ $cas_servers=array(
 $default_cas_server=key($cas_servers);
 
 // PhpCAS log file
-$phpCAS_logfile='/tmp/cas.log';
+$phpCAS_logfile='cas.log';
 
 // Local app URL (auto-detect on first acces if null)
 $service_url=null;