sheepdog : volume_resize return if running

fix : https://forum.proxmox.com/threads/sheepdog-disk-resize-not-working.31760/

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>

PVE/Storage/SheepdogPlugin.pm

@@ -379,6 +379,8 @@ sub volume_size_info {
 sub volume_resize {
     my ($class, $scfg, $storeid, $volname, $size, $running) = @_;
 
+    return 1 if $running;
+
     my ($vtype, $name, $vmid, $basename, $basevmid, $isBase) =
 	$class->parse_volname($volname);