platform: use also statvfs() to check for udevd

Check whether or not there is a running udevd by using statvfs() on
"/sys" and use access() as a fallback. This is in line with what is
done by systemd [1] and helps in case NM is not really running in a
container but has been confined by a MAC so it does not have full
access to sysfs (access() returns EACCES).

[1] https://github.com/systemd/systemd/blob/v246/src/basic/stat-util.c#L132

!639
26 jobs for master in 38 minutes and 58 seconds (queued for 21 seconds)
Status Job ID Name Coverage
  Test
passed #4875603
checkpatch

00:02:23

manual #4875642
allowed to fail manual
t_centos:7.5.1804
manual #4875646
allowed to fail manual
t_centos:7.6.1810
manual #4875651
allowed to fail manual
t_centos:7.7.1908
manual #4875657
allowed to fail manual
t_centos:7.8.2003
manual #4875661
allowed to fail manual
t_centos:8.1.1911
manual #4875681
allowed to fail manual
t_debian:10
manual #4875679
allowed to fail manual
t_debian:9
manual #4875686
allowed to fail manual
t_debian:sid
manual #4875683
allowed to fail manual
t_debian:testing
manual #4875611
allowed to fail manual
t_fedora:28
manual #4875616
allowed to fail manual
t_fedora:29
manual #4875623
allowed to fail manual
t_fedora:30
manual #4875627
allowed to fail manual
t_fedora:31
passed #4875631
t_fedora:32

00:38:19

manual #4875633
allowed to fail manual
t_fedora:33
manual #4875637
allowed to fail manual
t_fedora:rawhide
manual #4875665
allowed to fail manual
t_ubuntu:16.04
manual #4875669
allowed to fail manual
t_ubuntu:18.04
manual #4875676
allowed to fail manual
t_ubuntu:devel
manual #4875673
allowed to fail manual
t_ubuntu:rolling
 
  Deploy
passed #4875689
pages

00:00:14

passed pages:deploy

00:00:02

failed pages:deploy

00:00:00

failed pages:deploy

00:00:00

 
  Triage
passed #4875690
triage:issues

00:00:25