File _constraints of Package obs-server

<constraints>
  <overwrite>
    <conditions>
      <package>obs-server</package>
    </conditions>

    <hardware>
      <memory>
        <size unit="M">2000</size>
      </memory>
      <physicalmemory>
        <size unit="M">1500</size>
      </physicalmemory>
    </hardware>
  </overwrite>
</constraints>