Correct error handling when using cursor paginator

Previously we were catching an XmlProcessingexception around a method
that would never throw such an exception. The catch had been intended
for next().
diff --git a/src/com/google/enterprise/adaptor/sharepoint/SharePointAdaptor.java b/src/com/google/enterprise/adaptor/sharepoint/SharePointAdaptor.java
index 9e17469..5d73c6b 100644
--- a/src/com/google/enterprise/adaptor/sharepoint/SharePointAdaptor.java
+++ b/src/com/google/enterprise/adaptor/sharepoint/SharePointAdaptor.java
@@ -450,10 +450,13 @@
       CursorPaginator<SPContentDatabase, String> changesPaginator
           = client.getChangesContentDatabase(contentDatabase, changeId,
               isSp2010);
-      SPContentDatabase changes;
       try {
-        while ((changes = changesPaginator.next()) != null) {
+        while (true) {
           try {
+            SPContentDatabase changes = changesPaginator.next();
+            if (changes == null) {
+              break;
+            }
             client.getModifiedDocIds(changes, pusher);
           } catch (XmlProcessingException ex) {
             log.log(Level.WARNING, "Error parsing changes from content "