followup: free_image: just check if a file in general exist

don't require any specific file types, if something is here which can
be requested to delete over API/CLI it either comes from an API/CLI
operation and should be thus OK to delete, else a user caused the
creation of the special file and it either works and all is good or
the user gets notified as we check if unlink succeeded anyway

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

PVE/Storage/Plugin.pm

@@ -689,8 +689,7 @@ sub free_image {
     if (defined($format) && ($format eq 'subvol')) {
 	File::Path::remove_tree($path);
     } else {
-
-	if (! (-f $path || -l $path)) {
+	if (! -e $path) {
 	    warn "disk image '$path' does not exists\n";
 	    return undef;
 	}