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