private Privilege[] extractDropPriv(Privilege[] requiredPrivs) {
      if (requiredPrivs == null) {
        return null;
      }
      List<Privilege> privList = new ArrayList<Privilege>();
      for (Privilege priv : requiredPrivs) {
        if (priv.equals(Privilege.DROP)) {
          hasDropPrivilege = true;
        } else {
          privList.add(priv);
        }
      }
      return privList.toArray(new Privilege[0]);
    }
Checks the permissions for the given path and current user on Hadoop FS. If the given path
does not exists, it returns.
ql/src/java/org/apache/hadoop/hive/ql/security/authorization/StorageBasedAuthorizationProvider.java