Fix ssh connection caching stop method to work with openssh 6.5p1, which broke the old method.

Old ssh did not check the hostname passed to -O stop, so I had used "any".
But now ssh does check it! I think this happened as part of the client-side
hostname canonicalization changes in 6.5p1, but have not verified that
introduced the problem.

The symptom was that it would try to dns lookup "any", which often caused a
bit of a delay at shutdown. And the old ssh connection kept running, so
it would do it over and over again.

Fixed by using localhost, which hopefully reliably resolves to some address
that ssh will accept.. Also nukeFile the socket after ssh has been asked to
shutdown, just in case.

Annex/Ssh.hs

@@ -146,7 +146,7 @@ sshCleanup = go =<< sshCacheDir
 			withQuietOutput createProcessSuccess $
 				(proc "ssh" $ toCommand $
 					[ Params "-O stop"
-					] ++ params ++ [Param "any"])
+					] ++ params ++ [Param "localhost"])
 					{ cwd = Just dir }
 		liftIO $ nukeFile socketfile
 		-- Cannot remove the lock file; other processes may

debian/changelog

@@ -14,6 +14,8 @@ git-annex (5.20140307) UNRELEASED; urgency=medium
     the repository's description will now fail when multiple repositories
     match, rather than picking a repository at random.
     (So will --in=)
+  * Fix ssh connection caching stop method to work with openssh 6.5p1,
+    which broke the old method.
 
  -- Joey Hess <joeyh@debian.org>  Thu, 06 Mar 2014 16:17:01 -0400