logind: ignore failing close() on session-devices

logind: ignore failing close() on session-devices

Unfortunately, close() on a revoked/removed character-device fails with
ENODEV. I tried tracking this down in the kernel, but couldn't figure out
were exactly it comes from. However, can be easily reproduced with:
  fd = open("/dev/input/event0", O_RDWR);
  ioctl(fd, EVIOCREVOKE, 0);
  r = close(fd);
A second close on @fd would return EBADF so the close is actually valid.

We simply ignore close() errors for all session-devices as their access
may be revoked asynchronously, or the device might get unplugged.
We use close_nointr() in case anyone ever looks at the return value (or
anyone runs "grep 'close(' -r src/" to find broken close() calls).

Fixes:
  systemd-logind[31992]: Assertion 'close_nointr(fd) == 0' failed at src/shared/util.c:185, function close_nointr_nofail(). Aborting.