rbd: unmap volume after rename

When krbd is used, subsequent removal after an an operation
involving a rename could fail with
> librbd::image::PreRemoveRequest: 0x559b7506a470 \
> check_image_watchers: image has watchers - not removing
because the old mapping was still present.

For both operations with a rename, the owning guest should be offline,
but even if it weren't, unmap simply fails when the volume is in-use.

Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>

PVE/Storage/RBDPlugin.pm

@@ -482,6 +482,9 @@ sub create_base {
     );
     run_rbd_command($cmd, errmsg => "rbd rename '$name' error");
 
+    eval { $class->unmap_volume($storeid, $scfg, $volname); };
+    warn $@ if $@;
+
     my $running  = undef; #fixme : is create_base always offline ?
 
     $class->volume_snapshot($scfg, $storeid, $newname, $snap, $running);
@@ -817,6 +820,9 @@ sub rename_volume {
 	errmsg => "could not rename image '${source_image}' to '${target_volname}'",
     );
 
+    eval { $class->unmap_volume($storeid, $scfg, $source_volname); };
+    warn $@ if $@;
+
     $base_name = $base_name ? "${base_name}/" : '';
 
     return "${storeid}:${base_name}${target_volname}";