Bug fix in just-added unbounded methods for Zone.

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@2217 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/pta/DBM.java

@@ -320,7 +320,7 @@ public class DBM extends Zone
 	{
 		int i, n;
 		n = pta.numClocks;
-		for (i = 0; i < n + 1; i++) {
+		for (i = 1; i < n + 1; i++) {
 			if (!DB.isInfty(d[i][0])) {
 				return false;
 			}

prism/src/pta/DBMList.java

@@ -353,7 +353,7 @@ public class DBMList extends NCZone
 	{
 		int i, n;
 		n = pta.numClocks;
-		for (i = 0; i < n + 1; i++) {
+		for (i = 1; i < n + 1; i++) {
 			if (!clockIsUnbounded(i)) {
 				return false;
 			}