Commit c1023ee353705 introduced a split between mount flags and
path flags. It didn't initialize symlink_info::path_flags in
path_conv::check, because that's done in symlink_info::check.
However, there are two code paths expecting symlink_info::path_flags
being already initialized and both skip symlink_info::check.
Make sure symlink_info::path_flags is initalized to 0 early in
path_conv::check.
Fixes: c1023ee353705 ("Cygwin: path_conv: decouple path_types from mount types")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>