dm snapshot: rename dm_snap_exception to dm_exception

The exception structure is not necessarily just a snapshot
element (especially after we pull it out of dm-snap.c).

Renaming appropriately.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c
index cde5aa5..267801b 100644
--- a/drivers/md/dm-snap-transient.c
+++ b/drivers/md/dm-snap-transient.c
@@ -36,7 +36,7 @@
 }
 
 static int transient_prepare_exception(struct dm_exception_store *store,
-				       struct dm_snap_exception *e)
+				       struct dm_exception *e)
 {
 	struct transient_c *tc = store->context;
 	sector_t size = get_dev_size(store->cow->bdev);
@@ -51,7 +51,7 @@
 }
 
 static void transient_commit_exception(struct dm_exception_store *store,
-				       struct dm_snap_exception *e,
+				       struct dm_exception *e,
 				       void (*callback) (void *, int success),
 				       void *callback_context)
 {