fix ticks

git-svn-id: svn+ssh://svn.internal.sanger.ac.uk/repos/svn/pathsoft/artemis/trunk@10671 ee4ac58c-ac51-4696-9907-e4b3aa274f04

uk/ac/sanger/artemis/circular/digest/Utils.java

@@ -112,6 +112,9 @@ public class Utils
       div = 100000;
     int tickNum = sequenceLength / div;
     int tick = tickNum * (div / 10);
+    
+    if(tick < 1)
+      tick = 2;
     while ((sequenceLength % tick) < (div / 10))
     {
       tickNum++;