Change noCommon default for spray/copy

The default option of spray, is to dedup the ftslaves on the push or pull side, if there are multiple parts on the same node.

This means that there is a single threaded process pull or pushing a series of parts in series.
This can often mean that the throughput is significantly reduced if the target has more capacity (disk/net) than a single source.
Or, if it handling a compressed file, it is bound by a single ftslave process/thread decompressing.

We have a noCommon option to prevent this automatic reduction to 1 ftslave, but it's default is false.

Switch the default to true in dfuserver, service and eclwatch.