job: Move progress fields to Job

BlockJob has fields .offset and .len, which are actually misnomers today
because they are no longer tied to block device sizes, but just progress
counters. As such they make a lot of sense in generic Jobs.

This patch moves the fields to Job and renames them to .progress_current
and .progress_total to describe their function better.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
diff --git a/qemu-img.c b/qemu-img.c
index 700e4e1..976b437 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -863,9 +863,13 @@
     aio_context_acquire(aio_context);
     job_ref(&job->job);
     do {
+        float progress = 0.0f;
         aio_poll(aio_context, true);
-        qemu_progress_print(job->len ?
-                            ((float)job->offset / job->len * 100.f) : 0.0f, 0);
+        if (job->job.progress_total) {
+            progress = (float)job->job.progress_current /
+                       job->job.progress_total * 100.f;
+        }
+        qemu_progress_print(progress, 0);
     } while (!job_is_ready(&job->job) && !job_is_completed(&job->job));
 
     if (!job_is_completed(&job->job)) {