handle multibyte characters in name

handle multibyte characters in name

Many "git submodule" operations do not work on a submodule at a path whose
name is not in ASCII.

This is because "git ls-files" is used to find which paths are bound to
submodules to the current working tree, and the output is C-quoted by default
for non ASCII pathnames.

Tell "git ls-files" to not C-quote its output, which is easier than unwrapping
C-quote ourselves.

Signed-off-by: Fredrik Gustafsson <redacted>
Signed-off-by: Junio C Hamano <redacted>