ocfs2: Make ocfs2_slot_info private.

Just use osb_lock around the ocfs2_slot_info data.  This allows us to
take the ocfs2_slot_info structure private in slot_info.c.  All access
is now via accessors.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

fs/ocfs2/ocfs2.h

diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 6546cef..ee3f675 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -179,6 +179,7 @@
 #define OCFS2_DEFAULT_ATIME_QUANTUM	60
 
 struct ocfs2_journal;
+struct ocfs2_slot_info;
 struct ocfs2_super
 {
 	struct task_struct *commit_task;