AbstractMigrate: remove unused rsync and scp remainders
We have no call using rsync_cmd or scp_cmd here or any child class.
The only part where rsync is used is in the
PVE::Storage::storage_migrate call, but here both the command and the
RSYNC_RSH environment variable gets assembled there locally, so clean
this up here.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>