Merge branch 'ticket32672_041_squashed' into ticket32672_042_squashed_w_test

  o Minor features (directory authorities):

    - Directory authorities now reject descriptors from relays running Tor

      versions from the 0.2.9 and 0.4.0 series, but still allow the 0.3.5

      series. Resolves ticket 32672. Patch by Neel Chauhan.

  static const char please_upgrade_string[] =

    "Tor version is insecure or unsupported. Please upgrade!";

  /* Versions before Tor 0.2.9 are unsupported. Versions between 0.2.9.0 and

   * 0.2.9.4 suffer from bug #20499, where relays don't keep their consensus

   * up to date */

  if (!tor_version_as_new_as(platform,"0.2.9.5-alpha")) {

  /* Versions before Tor 0.3.5 are unsupported.

   *

   * Also, reject unstable versions of 0.3.5, since (as of this writing)

   * they are almost none of the network. */

  if (!tor_version_as_new_as(platform,"0.3.5.7")) {

    if (msg)

      *msg = please_upgrade_string;

    return true;

  }

  /* Series between Tor 0.3.0 and 0.3.4 inclusive are unsupported, and some

   * have bug #27841, which makes them broken as intro points. Reject them.

   *

   * Also reject unstable versions of 0.3.5, since (as of this writing)

   * they are almost none of the network. */

  if (tor_version_as_new_as(platform,"0.3.0.0-alpha-dev") &&

      !tor_version_as_new_as(platform,"0.3.5.7")) {

  /* Series between Tor 0.3.6 and 0.4.1.4-rc inclusive are unsupported.

   * Reject them. 0.3.6.0-alpha-dev only existed for a short time, before

   * it was renamed to 0.4.0.0-alpha-dev. */

  if (tor_version_as_new_as(platform,"0.3.6.0-alpha-dev") &&

      !tor_version_as_new_as(platform,"0.4.1.5")) {

    if (msg) {

      *msg = please_upgrade_string;

    }