direct mode merge relative path trickiness

This fixes 9 test suite failures. There are some tricky things going on
with the paths to the index file, and git's working directory, which
are hard to get right with relative paths. So, I switched back to absolute
here, at least for now.

Only 2 test suite failures remain on this branch, but there are other
potential problems the test suite doesn't catch. Including some calls to
setCurrentDirectory -- I was wrong and git-annex does do that in a few
places, like when generating a view.

Annex/Direct.hs

@@ -160,8 +160,8 @@ addDirect file cache = do
  -}
 mergeDirect :: Maybe Git.Ref -> Maybe Git.Ref -> Git.Branch -> Annex Bool -> Git.Branch.CommitMode -> Annex Bool
 mergeDirect startbranch oldref branch resolvemerge commitmode = exclusively $ do
-	reali <- fromRepo indexFile
-	tmpi <- fromRepo indexFileLock
+	reali <- liftIO . absPath =<< fromRepo indexFile
+	tmpi <- liftIO . absPath =<< fromRepo indexFileLock
 	liftIO $ copyFile reali tmpi
 
 	d <- fromRepo gitAnnexMergeDir
@@ -198,9 +198,12 @@ stageMerge d branch commitmode = do
 	merger <- ifM (coreSymlinks <$> Annex.getGitConfig)
 		( return Git.Merge.stageMerge
 		, return $ \ref -> Git.Merge.mergeNonInteractive ref commitmode
-		) 
-	inRepo $ \g -> merger branch $ 
-		g { location = Local { gitdir = Git.localGitDir g, worktree = Just d } }
+		)
+	inRepo $ \g -> do
+		wd <- liftIO $ absPath d
+		gd <- liftIO $ absPath $ Git.localGitDir g
+		merger branch $ 
+			g { location = Local { gitdir = gd, worktree = Just (addTrailingPathSeparator wd) } }
 
 {- Commits after a direct mode merge is complete, and after the work
  - tree has been updated by mergeDirectCleanup.