block: Rename BlockDriverAIOCB* to BlockAIOCB*

I'll use BlockDriverAIOCB with block backends shortly, and the name is
going to fit badly there.  It's a block layer thing anyway, not just a
block driver thing.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/qed.h b/block/qed.h
index 2b0e724..fc49804 100644
--- a/block/qed.h
+++ b/block/qed.h
@@ -128,7 +128,7 @@
 };
 
 typedef struct QEDAIOCB {
-    BlockDriverAIOCB common;
+    BlockAIOCB common;
     QEMUBH *bh;
     int bh_ret;                     /* final return status for completion bh */
     QSIMPLEQ_ENTRY(QEDAIOCB) next;  /* next request */