* Add creation of no-passphrase Protocol 2 RSA key in addition to Protocol 1 key. Currently Protocol 1 will continue to be generated, until we figure out an acceptable way to conditionalize this for old and new sites. * No longer generate authorized_keys2 file. All keys go in the main file, and the authorized_keys2 file is deleted if it exists, after successful creation of the main file. * When regenerating the Emulab keys, read the current .pub file in and delete the existing keys from the DB.