dde_rump: add extended rump_fs server test.

The run-script includes the usage of part_blk, blk_cache, and ahci.
rump_fs: mount file system on-demand

The rumpkernel will now mount the specified file system on the first
session request. In addition it will be unmounted when the last client
closes its session. This way we make sure the used file system is
properly unmounted and all pending buffers are synced or rather flushed.
dde_rump: interim update of nblibs XXX
dde_rump: interim fix for new nblibs XXX
rump_fs: initial fsck support XXX