Do not switch to read-only mode in case of -EINTR and some
other obvious cases. Switch to RO mode only when we do not
know what is the error.
Reported-by: NVinit Agnihotri <vinit.agnihotri@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>