Generate index with only '/'.
* perl/Amanda/Application/Zfs.pm: Add $self->{filesystem} on some
  command, improve zfs_build_snapshotname.
* server-src/list_dir.c (add_dir_list_item): Check if same dump.


git-svn-id: https://amanda.svn.sourceforge.net/svnroot/amanda/amanda/branches/3_1@3983 a8d146d6-cc15-0410-8900-af154a0219e0