cli-tests: fix broken test

I'm not sure how this passed the GitHub checks.

Author: ebiggers

cli-tests/t_encrypt_login.sh

@@ -89,7 +89,7 @@ show_status false
 
 begin "Test that linked protector works even if UUID link is broken"
 echo TEST_USER_PASS | fscrypt encrypt --quiet --source=pam_passphrase --user="$TEST_USER" "$dir"
-protector=$(get_login_protector)
+protector=$(_get_login_descriptor)
 link_file=$MNT/.fscrypt/protectors/$protector.link
 [ -e "$link_file" ] || _fail "$link_file does not exist"
 sed -i 's/UUID=.*/UUID=00000000-0000-0000-0000-000000000000/' "$link_file"