Add tests for flavors command.

Also refactors `show flavors` to use it's own provider.
Use :provider => 'rackspace' when building Provider.

This will hopefully make the test less brittle on version changes.
Merge pull request #80 from dkinzer/add-flavors-tests

Add unit tests for flavors command.
Adds a --no_passwd_lock option to 'create server'

Supplying any non-nil value to --no_passwd_lock will have rumm create a server with a passwd

If this option is not provided, the root user will have had  passwd -l applied.
Merge pull request #82 from rackspace/no_passwd_lock

Adds a --no_passwd_lock option to 'create server'