Fixed broken test from last commit

Author: jyemin

src/test/com/mongodb/DBObjectTest.java

@@ -146,7 +146,7 @@ public void testInnerDot() {
             _colTest.save(dbObject);
         }
         catch (IllegalArgumentException e) {
-            if (e.getMessage().startsWith("fields stored in the db can't have . in them")) {
+            if (e.getMessage().startsWith("Document field names can't have a . in them. (Bad Key: 'test.member.name')")) {
                 thrown = true;
             }
         }