avoid writing same symlink twice in a row

Oddly, the second write did not cause it to lose the mtime inherited
from the file being added, although the mtime was not provided to that
write but only to the first. I don't quite know why that worked before!

Annex/Ingest.hs

@@ -341,8 +341,8 @@ addLink ci file key mcache = ifM (coreSymlinks <$> Annex.getGitConfig)
 
 addSymlink :: RawFilePath -> Key -> Maybe InodeCache -> Annex ()
 addSymlink file key mcache = do
-	l <- makeLink file key mcache
-	addAnnexLink l file
+	linktarget <- makeLink file key mcache
+	stageSymlink file =<< hashSymlink linktarget
 
 {- Parameters to pass to git add, forcing addition of ignored files.
  -