clean up after migration and drop the dnsTTL override

tsa/howto/ganeti.mdwn

@@ -367,7 +367,7 @@ Import procedure:
 
  11. change IP address in the following locations:
 
-     * LDAP (`ipHostNumber` field, but also change the `physicalHost` and `l` fields!)
+     * LDAP (`ipHostNumber` field, but also change the `physicalHost` and `l` fields!).  Also drop the dnsTTL attribute while you're at it.
      * Puppet (grep in tor-puppet source, run `puppet agent -t; ud-replicate` on pauli)
      * DNS (grep in tor-dns source, `puppet agent -t; ud-replicate` on nevii)
      * nagios (don't forget to change the parent)