Use lowercase hash directories for locationlog files

to avoid some issues with git on OSX with the mixed-case directories. No
migration is needed; the old mixed case hash directories are still read;
new information is written to the new directories.

Remote/Directory.hs

@@ -66,7 +66,7 @@ directorySetup u c = do
 	return $ M.delete "directory" c
 
 dirKey :: FilePath -> Key -> FilePath
-dirKey d k = d </> hashDir k </> f </> f
+dirKey d k = d </> hashDirMixed k </> f </> f
 	where
 		f = keyFile k