handle empty sample data

git-svn-id: svn+ssh://svn.internal.sanger.ac.uk/repos/svn/pathsoft/artemis/trunk@15171 ee4ac58c-ac51-4696-9907-e4b3aa274f04

uk/ac/sanger/artemis/components/variant/VCFRecord.java

@@ -91,6 +91,8 @@ class VCFRecord
    */
   private String getSampleDataString()
   {
+    if(data == null)
+      return "";
     StringBuffer buff = new StringBuffer();
     for(int i=0; i<data.length; i++)       // loop over samples
     {