get_running_processes: don't list 'kernel' as a pid
get_running_processes: don't list 'kernel' as a pid

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.

Change-Id: I5e99cff3218388468660770c2e304494023a9099

openstack/bareon,openstack/bareon