jfs: Fix early release of acl in jfs_get_acl

BugLink: http://bugs.launchpad.net/ubuntu/+bug/396780



Commit 073aaa1b "helpers for acl
caching + switch to those" introduced new helper functions for
acl handling but seems to have introduced a regression for jfs as
the acl is released before returning it to the caller, instead of
leaving this for the caller to do.
This causes the acl object to be used after freeing it, leading
to kernel panics in completely different places.

Thanks to Christophe Dumez for reporting and bisecting into this.

Reported-by: Christophe Dumez <dchris@gmail.com>
Tested-by: Christophe Dumez <dchris@gmail.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>