block: Add error parameter to blk_insert_bs()

Now that blk_insert_bs() requests the BlockBackend permissions for the
node it attaches to, it can fail. Instead of aborting, pass the errors
to the callers.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
index 1dd1cfa..143ce96 100644
--- a/tests/test-blockjob.c
+++ b/tests/test-blockjob.c
@@ -60,7 +60,7 @@
     bs = bdrv_open("null-co://", NULL, NULL, 0, &error_abort);
     g_assert_nonnull(bs);
 
-    blk_insert_bs(blk, bs);
+    blk_insert_bs(blk, bs, &error_abort);
     bdrv_unref(bs);
 
     if (name) {