docker-cli: Avoid to use github.com/moby/sys/mount on NetBSD

The patch was just a build fix without needed features implemented, for the
moment let's just avoid using it to hopefully avoid less problems.

docker-cli/distinfo

@@ -4,4 +4,4 @@ SHA1 (docker-cli-20.10.1.tar.gz) = 475dfcec26cb528894c91c43fba95ec4eb4b3bb6
 RMD160 (docker-cli-20.10.1.tar.gz) = b58ff4ca635356dbc0cd58b25e9fd673e0c06d04
 SHA512 (docker-cli-20.10.1.tar.gz) = 47d15647db2a4ca6de29ba1d67aa198b9baa4af9ccf08e92e2a7222f28391567f8a2f6beeb4d8d80fa16a05ce8902de16b8951da2a34cbed9e27c72e0443c3e8
 Size (docker-cli-20.10.1.tar.gz) = 7705467 bytes
-SHA1 (patch-vendor_github.com_moby_sys_mount_flags__bsd.go) = c07b122c65fb43eb92bc3aef402f86b05bae8345
+SHA1 (patch-vendor_github.com_docker_docker_pkg_system_rm.go) = 35c15352e2d3e610bdef85a15947a7459cfc17a2

docker-cli/patches/patch-vendor_github.com_docker_docker_pkg_system_rm.go

@@ -0,0 +1,14 @@
+$NetBSD$
+
+Fix build for NetBSD.
+
+github.com/sys/mount needs to be ported on NetBSD.
+
+--- vendor/github.com/docker/docker/pkg/system/rm.go.orig	2020-12-15 02:27:14.000000000 +0000
++++ vendor/github.com/docker/docker/pkg/system/rm.go
+@@ -1,4 +1,4 @@
+-// +build !darwin,!windows
++// +build !darwin,!netbsd,!windows
+ 
+ package system // import "github.com/docker/docker/pkg/system"
+ 

docker-cli/patches/patch-vendor_github.com_moby_sys_mount_flags__bsd.go

@@ -1,16 +0,0 @@
-$NetBSD$
-
-Add support for NetBSD.
-
-Shared upstream via:
-
- https://github.com/moby/sys/pull/60
-
---- vendor/github.com/moby/sys/mount/flags_bsd.go.orig	2020-12-15 02:27:14.000000000 +0000
-+++ vendor/github.com/moby/sys/mount/flags_bsd.go
-@@ -1,4 +1,4 @@
--// +build freebsd openbsd
-+// +build freebsd netbsd openbsd
- 
- package mount
-