Removes unnecessary output from rsync
Removes unnecessary output from rsync

Before copying ephemeral storage using `rsync` CF verifies if `rsync` is
installed by calling `rsync --help` which produces a lot of unnecessary
output. This patch reduces amount of output produced by redirecting it
to `/dev/null`.

MirantisWorkloadMobility/CloudFerry,mgrygoriev/CloudFerry,SVilgelm/CloudFerry,SVilgelm/CloudFerry,MirantisWorkloadMobility/CloudFerry,SVilgelm/CloudFerry,mgrygoriev/CloudFerry,mgrygoriev/CloudFerry,MirantisWorkloadMobility/CloudFerry,mgrygoriev/CloudFerry,MirantisWorkloadMobility/CloudFerry,SVilgelm/CloudFerry