Add NPE catch

Author: clicman

datajack-api/src/main/java/ru/sbtqa/tag/datajack/providers/AbstractDataProvider.java

@@ -97,6 +97,9 @@ public TestDataProvider get(String key) throws DataException {
      */
     @Override
     public TestDataProvider getByPath(String path) throws DataException {
+        if (path == null) {
+            throw new DataException("The path is null. Check your configuration");
+        }
         return parseTestDataProvider(path);
     }