get the timzone automatic on ubuntu/debian

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/branches/2.8@16896 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd

xCAT-server/sbin/xcatconfig

@@ -1096,6 +1096,10 @@ sub initDB
         elsif ( is_lsb_ubuntu() || is_debian() )
         {
             $tz = discover_timezone_ubuntu;
+            if (!$tz){
+                $tz = `cat /etc/timezone`;
+                chomp $tz;
+            }
         }
         else
         {