Sync with 2.12.1

diff --combined Documentation/git.txt
index df0941d456b0fa1ab3be4f459f73edd3145ffb32,25560f69ff9b7208db31261d2283d91df91601bc..3f75af872c040ade3bebdf8ae196e158f0688141
--- 1/Documentation/git.txt
--- 2/Documentation/git.txt
+++ b/Documentation/git.txt
@@@ -44,9 -44,10 +44,10 @@@ unreleased) version of Git, that is ava
  branch of the `git.git` repository.
  Documentation for older releases are available here:
  
- * link:v2.12.0/git.html[documentation for release 2.12.0]
+ * link:v2.12.1/git.html[documentation for release 2.12.1]
  
  * release notes for
+   link:RelNotes/2.12.1.txt[2.12.1].
    link:RelNotes/2.12.0.txt[2.12].
  
  * link:v2.11.1/git.html[documentation for release 2.11.1]
@@@ -1025,12 -1026,6 +1026,12 @@@ Usually it is easier to configure any d
  personal `.ssh/config` file.  Please consult your ssh documentation
  for further details.
  
 +`GIT_SSH_VARIANT`::
 +      If this environment variable is set, it overrides Git's autodetection
 +      whether `GIT_SSH`/`GIT_SSH_COMMAND`/`core.sshCommand` refer to OpenSSH,
 +      plink or tortoiseplink. This variable overrides the config setting
 +      `ssh.variant` that serves the same purpose.
 +
  `GIT_ASKPASS`::
        If this environment variable is set, then Git commands which need to
        acquire passwords or passphrases (e.g. for HTTP or IMAP authentication)