Log Message:
Update ruby-net-ssh to 2.5.2.

=== 2.5.2 / 25 May 2012

* Fix for Net::SSH::KnownHosts::SUPPORTED_TYPE [Marco Sandrini]

=== 2.5.1 / 24 May 2012

* Added missing file to manifest [Marco Sandrini]

=== 2.5.0 / 24 May 2012

* Implement many algorithms [Ryosuke Yamazaki]
  * Key Exchange
     * diffie-hellman-group14-sha1
     * ecdh-sha2-nistp{256,384,521}
   * Host Key
     * ecdsa-sha2-nistp{256,384,521}
   * Authentication
     * ecdsa-sha2-nistp{256,384,521}
   * HMAC
     * hmac-ripemd160
   * Cipher:
     * aes{128,192,256}-ctr
     * camellia{128,192,256}-ctr
     * blowfish-ctr
     * cast128-ctr
     * 3des-ctr
     * arcfour (has problems with weak keys, and should be used with caution)
     * camellia{128,192,256}-cbc

=== 2.4.0 / 17 May 2012

* Support for JRuby + Pageant + Windows [arturaz]