Fix pep8 violations in peer/pce.py
Fix pep8 violations in peer/pce.py

Change-Id: I79470c5ac5bacd022f82d7b444a9d563beb6cb45
Signed-off-by: Thanh Ha <09ea4d3a79c8bee41a16519f6a431f6bc0fd8d6f@linuxfoundation.org>

inocybe/odl-bgpcep,inocybe/odl-bgpcep,opendaylight/bgpcep,bigdataops/bgpcep,bigdataops/bgpcep