dm: rename request variables to bios

Use 'bio' in the name of variables and functions that deal with
bios rather than 'request' to avoid confusion with the normal
block layer use of 'request'.

No functional changes.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 7f24190..e2ea977 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1072,8 +1072,8 @@
 	if (r)
 		goto err_free_context;
 
-	ti->num_flush_requests = 1;
-	ti->num_discard_requests = 1;
+	ti->num_flush_bios = 1;
+	ti->num_discard_bios = 1;
 	ti->per_bio_data_size = sizeof(struct dm_raid1_bio_record);
 	ti->discard_zeroes_data_unsupported = true;