Sqlite: Improve LastChangedRowId

Change-Id: I2fe559d4b40f93561e44eb138119416291dc7d41
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/libs/sqlite/lastchangedrowid.h

@@ -114,6 +114,8 @@ public:
         return rowId;
     }
 
+    bool lastRowIdIsValid() { return lastRowId >= 0; }
+
 public:
     DatabaseInterface &database;
     DatabaseInterface::UpdateCallback callback;