qemu-img: Set the ID of the block job in img_commit()

img_commit() creates a block job without an ID. This is no longer
allowed now that we require it to be unique and well-formed. We were
solving this by having a fallback in block_job_create(), but now that
we extended the API of commit_active_start() we can finally set an
explicit ID and revert that change.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qemu-img.c b/qemu-img.c
index a162f34..969edce 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -920,7 +920,7 @@
         .bs   = bs,
     };
 
-    commit_active_start(NULL, bs, base_bs, 0, BLOCKDEV_ON_ERROR_REPORT,
+    commit_active_start("commit", bs, base_bs, 0, BLOCKDEV_ON_ERROR_REPORT,
                         common_block_job_cb, &cbi, &local_err);
     if (local_err) {
         goto done;