qemu-img/qemu-io: don't prompt for passwords if not required

The qemu-img/qemu-io tools prompt for disk encryption passwords
regardless of whether any are actually required. Adding a check
on bdrv_key_required() avoids this prompt for disk formats which
have been converted to the QCryptoSecret APIs.

This is just a temporary hack to ensure the block I/O tests
continue to work after each patch, since the last patch will
completely delete all the password prompting code.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qemu-io.c b/qemu-io.c
index bc12953..c08b495 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -70,7 +70,7 @@
     }
 
     bs = blk_bs(qemuio_blk);
-    if (bdrv_is_encrypted(bs)) {
+    if (bdrv_is_encrypted(bs) && bdrv_key_required(bs)) {
         char password[256];
         printf("Disk image '%s' is encrypted.\n", name);
         if (qemu_read_password(password, sizeof(password)) < 0) {