blockjob: Update description of the 'id' field

The 'id' field of the BlockJob structure will be able to hold any ID,
not only a device name. This patch updates the description of that
field and the error messages where it is being used.

Soon we'll add the ability to set an arbitrary ID when creating a
block job.

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/blockjob.c b/blockjob.c
index 205da9d..ce0e27c 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -290,7 +290,8 @@
 void block_job_complete(BlockJob *job, Error **errp)
 {
     if (job->pause_count || job->cancelled || !job->driver->complete) {
-        error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id);
+        error_setg(errp, "The active block job '%s' cannot be completed",
+                   job->id);
         return;
     }