Merge branch 'es/checkout-index-temp'

"git checkout-index --temp=$target $path" did not work correctly for paths outside the current subdirectory in the project. * es/checkout-index-temp: checkout-index: fix --temp relative path mangling t2004: demonstrate broken relative path printing t2004: standardize file naming in symlink test t2004: drop unnecessary write-tree/read-tree t2004: modernize style