Catch more generic `FileSystemException` in `NamedPipeSocket` (#1418)

When npipe is busy, it throws the following exception:
`java.nio.file.FileSystemException: \\.\pipe\docker_engine: All pipe instances are busy.`

The previous, RandomAccessFile-base implementation was catching it as `FileNotFoundException`.
But the NIO-based one seems to be throwing a generic `FileSystemException`.