pseudofs: do not check READ_ATTR bit for unix

Skip the check, if we ask for ACE4_READ_ATTRIBUTES as unix
always allows it.

Acked-by: Paul Millar
Target: master, 0.9, 0.8, 0.7
(cherry picked from commit dd7b5a83c6151801af79892c90b9e5acd29da0f7)
Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>