bug#27168: eshell/sudo doesn't work with protected directories

[Yegor Timoshenko]

Example (In M-x eshell):

cd /tmp
mkdir a
touch a/b
sudo chmod 700 a
sudo chown root:wheel a
sudo ls a

Expected output:

b

Instead I get:

/bin/ls: cannot open directory 'a': Permission denied

sudo cat a/b, etc. also don't work. I've found this problem while trying to cat my /etc/sudoers file:

$ sudo cat /etc/sudoers
Opening input file: Permission denied, /etc/sudoers