blockdev: Plug memory leak in blockdev_init()

blockdev_init() leaks bs_opts when qemu_opts_create() fails, i.e. when
the ID is bad.  Missed in commit ec9c10d2.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NBenoit Canet <benoit@irqsave.net>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
(cherry picked from commit 6376f952)
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

blockdev.c

@@ -334,7 +334,7 @@ static DriveInfo *blockdev_init(QDict *bs_opts,
     opts = qemu_opts_create(&qemu_common_drive_opts, id, 1, &error);
     if (error_is_set(&error)) {
         error_propagate(errp, error);
-        return NULL;
+        goto err_no_opts;
     }
 
     qemu_opts_absorb_qdict(opts, bs_opts, &error);
@@ -535,8 +535,9 @@ err:
     QTAILQ_REMOVE(&drives, dinfo, next);
     g_free(dinfo);
 early_err:
-    QDECREF(bs_opts);
     qemu_opts_del(opts);
+err_no_opts:
+    QDECREF(bs_opts);
     return NULL;
 }