Be on the correct Filesystem for output to S3. (0.7.0 version)

c.f. #185. New `MscrOutputChannel.collectOutputs` has slipped in `fs.mkdirs(...)`
instead of `FileSystem.get(...).mkdirs(...)`.

Most of the fix is in `FileSystems` for wider application.

```
You possibly called FileSystem.get(conf) when you should have called FileSystem.get(uri, conf) to obtain a file system supporting your path.
	at org.apache.hadoop.fs.FileSystem.checkPath(FileSystem.java:384)
	at org.apache.hadoop.hdfs.DistributedFileSystem.getPathName(DistributedFileSystem.java:129)
	at org.apache.hadoop.hdfs.DistributedFileSystem.mkdirs(DistributedFileSystem.java:321)
	at org.apache.hadoop.fs.FileSystem.mkdirs(FileSystem.java:1128)
	at com.nicta.scoobi.impl.plan.mscr.MscrOutputChannel$$anonfun$collectOutputs$1$$anonfun$apply$1.apply(OutputChannel.scala:94)
	at com.nicta.scoobi.impl.plan.mscr.MscrOutputChannel$$anonfun$collectOutputs$1$$anonfun$apply$1.apply(OutputChannel.scala:93)
  at scala.Option.foreach(Option.scala:197)
...
```