RabbitMQ doesn't work for App Engine apps in EC2

[shatterednirvana]

When Google App Engine apps start in Amazon EC2 in a standard two node deployment, they throw this stack trace:

WARNING  2012-05-17 08:17:34,392 rdbms_mysqldb.py:90] The rdbms API is not available because the MySQLdb library could not be loaded.
ERROR    2012-05-17 08:17:37,717 base_connection.py:119] BlockingConnection: Socket Error on 3: 104
ERROR    2012-05-17 08:17:40,720 base_connection.py:119] BlockingConnection: Socket Error on 3: 104
ERROR    2012-05-17 08:17:40,721 dev_appserver_main.py:688] <class 'pika.exceptions.ChannelClosed'>:

Right now we just see this for Sisyphus, as it's the first App Engine app to start and it blocks all others from starting.

[shatterednirvana]

Note that it does work fine for a two node Xen deployment - maybe a public / private IP problem with RabbitMQ or where we point App Engine at for RabbitMQ?

[shatterednirvana]

Turns out the problem was caused by how we start nodes with the rabbitmq_slave role - got the fix from Vaibav, tested, and verified it on two node Xen and EC2 deployments. Fixed as of 797bffc.