init-ceph: use remote config when starting daemons on remote nodes (-a)

If you use -a to start a remote daemon, assume the remote config is present
instead of pushing the local config.  This makes more sense and simplifies
things.

Note that this means that -a in concert with -c foo means that foo must
also be present on the remote node in the same path.  That, however, is a
use case that I don't particularly care about right now.  :)

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>