orte/util: revamp orte_attr_unload() to keep valgrind happy

reorder tests to avoid valgrind complaining about uninitialized variables

Signed-off-by: Gilles Gouaillardet <gilles@rist.or.jp>

orte/util/attr.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2014-2016 Intel, Inc. All rights reserved
- * Copyright (c) 2014-2016 Research Organization for Information Science
+ * Copyright (c) 2014-2017 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
  * $COPYRIGHT$
  *
@@ -497,8 +497,8 @@ static int orte_attr_unload(orte_attribute_t *kv,
         return OPAL_ERR_TYPE_MISMATCH;
     }
     if (NULL == data  ||
-        (NULL == *data && OPAL_STRING != type && OPAL_BYTE_OBJECT != type &&
-         OPAL_BUFFER != type && OPAL_PTR != type)) {
+        (OPAL_STRING != type && OPAL_BYTE_OBJECT != type &&
+         OPAL_BUFFER != type && OPAL_PTR != type && NULL == *data)) {
         assert(0);
         OPAL_ERROR_LOG(OPAL_ERR_BAD_PARAM);
         return OPAL_ERR_BAD_PARAM;