Fix regression introduced in c51c9c7

Not all nodes might be on the storage network anymore, so we could crash
with:

Exception undefined method `[]' for nil:NilClass /opt/dell/crowbar_framework/app/models/ceph_service.rb:117:in `apply_role_pre_chef_call'
/opt/dell/crowbar_framework/app/models/service_object.rb:1213:in `apply_role'
/opt/dell/crowbar_framework/app/models/service_object.rb:1535:in `active_update'
/opt/dell/crowbar_framework/app/models/service_object.rb:726:in `proposal_commit'
/opt/dell/crowbar_framework/app/controllers/barclamp_controller.rb:391:in `proposal_update'
Merge pull request #72 from vuntz/fix-crash

Fix regression introduced in c51c9c7
Port RadosGW support from upstream cookbook.

add migration script

/srv/www/* owned by root:

no need to restart apache2 after apache_module and web_app

subscribe the service, isntead of notifying for config file
Added keystone configuration for RadosGW, to provide swift API for
openstack services.
Show a conflict message when swift is already deployed

write necessary keystone parts into /etc/ceph/ceph.conf

use /var/run/ceph-radosgw for radosgw related stuff

extra ceph-authtool call should not be needed

no need to check for 'done' file (but the file itself might be needed
for some debian init scripts)

set APACHE_MPM value

prevent nil.empty?
Convert OpenSSL certificates that Keystone uses for creating the requests to the nss db format

certs must be prepared before service start

chown all the files

ResellerAdmin role is needed

convert keystone certs only with PKI

node does not have to be keystone: get certificate info from keystone instance
(requires fix in keystone)
comment dependencies
create done file for ubuntu only
set ownership for ceph.client.radosgw keyring
rewrite converting certificates so the generation does not need
to happen always (patch from vuntz)
move possible apache restart to the end
set the non-default port, so it can work with Horizon
write ports for listening (not correct yet)
save listening ports to extra attribute so it is not lost
save the node, remove duplicates