void addMissingPrivilege(SQLPrivTypeGrant newPrivWGrant) {
      SQLPrivTypeGrant matchingPrivWGrant = priv2privWithGrant.get(newPrivWGrant.getPrivType());
      if (matchingPrivWGrant != null) {
        if (matchingPrivWGrant.isWithGrant() || !newPrivWGrant.isWithGrant()) {
          // the existing entry already has grant, or new priv does not have
          // grant
          // no update needs to be done.
          return;
        }
      }
      // add the new entry
      priv2privWithGrant.put(newPrivWGrant.getPrivType(), newPrivWGrant);
    }
Capture privileges that are missing. If privilege "X with grant" and "X without grant"
are reported missing, capture only "X with grant". This is useful for better error messages.
ql/src/java/org/apache/hadoop/hive/ql/security/authorization/plugin/sqlstd/RequiredPrivileges.java