Tramp fails to copy larger files from IPv6 hosts via scp

[Orivej Desh]

Current Tramp fails to copy files from IPv6 addressed hosts because it
does not add square brackets around the IP address.  Relevant debug log:

00:51:36.493926 tramp-do-copy-or-rename-file (0) # Copying 
/scp:[2a02::8184]:/bin/bash to /tmp/tramp.20043vTu.py...
00:51:36.495317 tramp-do-copy-or-rename-file-out-of-band (6) # /bin/zsh -c scp 
-p -q -r -o ControlMaster=auto -o ControlPath='tramp.%C' -o ControlPersist=no 
2a02\:\:8184\:/bin/bash /tmp/tramp.20043vTu.py && echo tramp_exit_status 0 || 
echo tramp_exit_status 1

The following change fixes it for me because scp accepts any host
address (IPv6, IPv4, or hostname) in the brackets.

--- a/lisp/tramp-sh.el
+++ b/lisp/tramp-sh.el
@@ -5136,2 +5136,2 @@ (defun tramp-make-copy-program-file-name (vec)
-      (shell-quote-argument (format "address@hidden:%s" user host localname)))
-     (t (shell-quote-argument (format "%s:%s" host localname))))))
+      (shell-quote-argument (format "address@hidden:%s" user host localname)))
+     (t (shell-quote-argument (format "[%s]:%s" host localname))))))