block: fix bad definition of BIO_RW_SYNC

We can't OR shift values, so get rid of BIO_RW_SYNC and use BIO_RW_SYNCIO
and BIO_RW_UNPLUG explicitly. This brings back the behaviour from before
213d9417fec62ef4c3675621b9364a667954d4dd.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blktrace.c b/block/blktrace.c
index 39cc3bf..7cf9d1f 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -142,7 +142,7 @@
 
 	what |= ddir_act[rw & WRITE];
 	what |= MASK_TC_BIT(rw, BARRIER);
-	what |= MASK_TC_BIT(rw, SYNC);
+	what |= MASK_TC_BIT(rw, SYNCIO);
 	what |= MASK_TC_BIT(rw, AHEAD);
 	what |= MASK_TC_BIT(rw, META);
 	what |= MASK_TC_BIT(rw, DISCARD);