eina_value: return null when eina_value_pget failed

Summary:
Add return value check.
found by coverity.

Reviewers: Hermet

Reviewed By: Hermet

Subscribers: cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D7107

src/lib/eo/Eo.h

@@ -2130,7 +2130,7 @@ eina_value_object_get(Eina_Value *v)
    if (eina_value_type_get(v) != EINA_VALUE_TYPE_OBJECT)
      return NULL;
 
-   eina_value_pget(v, &r);
+   if (!eina_value_pget(v, &r)) return NULL;
    return r;
 }