
fuser shows some of kernel accesses (mount points, swap files, etc)
using the string 'kernel' as a pid. Ignore such a pseudo-pid to
avoid the spurious errors and noise in the logs.
This CR effectively re-applies #245654 [0] which was merged
five days ago, but was accidentally reverted by #246575 [1]
due to some unknown issues during merge to master.
This could easily be seen from commit to master on GitHub [2]
[0] - https://review.openstack.org/#/c/245654
[1] - https://review.openstack.org/#/c/246575
[2] - c33563d561
Change-Id: Ia0cb7ef41812d854b53e52fbb4e06fd86622fb87