Update recursive cp for config files

Some projects have configs in project/etc/project, whilst others have
configs in project/etc.  This change will check for project/etc/project
so that we're copying files into place correctly.

We also move this code into a ruby_block so that the conditional code
is evaluated at execution time and not compile time (when
/opt/openstack does not yet exist).  It may be cleaner to create
attributes for this to indicate where to copy configs from, but for now
this appears to work fine.