Bug fix in reward struct print out - breaks digital clocks output with un-named rewards structs.

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@4715 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/parser/ast/RewardStruct.java

@@ -134,7 +134,7 @@ public class RewardStruct extends ASTElement
 		String s = "";
 		
 		s += "rewards";
-		if (name != null) s += " \""+name+"\"";
+		if (name != null && name.length() > 0) s += " \""+name+"\"";
 		s += " \n\n";
 		n = getNumItems();
 		for (i = 0; i < n; i++) {