Subversion+SSHでKilled by signal 15.が出る時は環境変数SVN_SSHを書き換える時のみ出る

つい最近までなんでだろーなーとか思ってたら海外のMLにSVN_SSHを上書きしている時で、かつssh -qを入れてないと出るよとか乗ってました。
http://old.nabble.com/svn%2Bssh----Killed-by-signal-15.-td26226917.html

subversion/libsvn_ra_svn/client.c:

  /* We have one predefined tunnel scheme, if it isn't overridden by config. */
  if (!val && strcmp(tunnel, "ssh") == 0)
    {
      /* Killing the tunnel agent with SIGTERM leads to unsightly
       * stderr output from ssh, unless we pass -q.
       * The "-q" option to ssh is widely supported: all versions of
       * OpenSSH have it, the old ssh-1.x and the 2.x, 3.x ssh.com
       * versions have it too. If the user is using some other ssh
       * implementation that doesn't accept it, they can override it
       * in the [tunnels] section of the config. */
      val = "$SVN_SSH ssh -q";
    }

うーん、しらんかった。
とりあえずbash,tcsh,zsh全てSVN_SSHをssh -q hogehogeみたいに変更。