remove config files when run clean.sh
remove config files when run clean.sh

Currently we don't remove Ceilometer config files when ./clean.sh
is run, which should be fixed because it will bite developers when
they test change related to devstack script.

Note, this patch also removes ceilometer api log files when WSGI
is not enabled.

Change-Id: I3fd62787708cf64d1860b2b64d25773e79b17fe9
Closes-Bug: #1509253

ityaptin/ceilometer,openstack/ceilometer,idegtiarov/ceilometer,ityaptin/ceilometer,idegtiarov/ceilometer,openstack/ceilometer