Fix a problem with OpenSSH 7 in Tramp

* lisp/net/tramp-sh.el (tramp-ssh-controlmaster-options): Set also
"ConnectTimeout" during test.  Otherwise, OpenSSH 7 will hang.

diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index e61b0ce526a90ceec0e7ab9ef451256c2aed44e5..9b001a90e78e83248015fa3bbcf0ae9390d01d9e 100644 (file)
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -4592,8 +4592,10 @@ Goes through the list `tramp-inline-compress-commands'."
                (with-temp-buffer
                  ;; We use a non-existing IP address, in order to
                  ;; avoid useless connections, and DNS timeouts.
+                 ;; Setting ConnectTimeout is needed since OpenSSH 7.
                  (tramp-call-process
-                  vec "ssh" nil t nil "-o" "ControlPath=%C" "0.0.0.1")
+                  vec "ssh" nil t nil
+                  "-o" "ConnectTimeout=1" "-o" "ControlPath=%C" "0.0.0.1")
                  (goto-char (point-min))
                  (setq tramp-ssh-controlmaster-options
                        (concat tramp-ssh-controlmaster-options