dlm: use idr_for_each_entry() in recover_idr_clear() error path

Convert recover_idr_clear() to use idr_for_each_entry() instead of
idr_for_each().  It's somewhat less efficient this way but it shouldn't
matter in an error path.  This is to help with deprecation of
idr_remove_all().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christine Caulfield <ccaulfie@redhat.com>
Cc: David Teigland <teigland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>