Implement delayed restore in bextract for acl and xattr.

Just as in the filed we need to extract the ACL and XATTR data streams
after we have restore the file mode on the file otherwise the setting
of the file mode could clear any acl or extended attributes.

Fixes #177:  Restore of acls and extended attributes in bextract needs
             to happen after restore file mode.
Add debian 7 support.
Add missing storage daemon config needed for NDMP.
Fix typo in NDMPlevelmap table definition.
Added btrfs to disk-only default config

Signed-off-by: Marco van Wieringen <marco.van.wieringen@bareos.com>
Fix problem with fastlz compression.
Number of subscriptions can be checked

The number of subscribed clients can be set in
the director ressource, e.g.

Subscriptions = 2

When the number of clients is bigger than the
configured limit, each job gets the following
message:

JobId 7: Warning: Subscriptions exceeded: (used/total) (3/2)

Also, the status of the subscriptions can be checked via
* status subscriptions
Warning! No available subscriptions: -1 (3/2) (used/total)

Nothing else than the warning is issued, no enforcement on
backup, restore or any other operation will happen.

Fixes #152: report if number of subscribed clients is exceeded.

Signed-off-by: Marco van Wieringen <marco.van.wieringen@bareos.com>