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

diff --cc builtin/checkout-index.c
Simple merge