remove pep8 and strict lxml version from setup.py
remove pep8 and strict lxml version from setup.py

Change-Id: I671f3e924641cdfdfb5d20d0b0e3c77e1dc714e2

openstack/networking-bigswitch,stackforge/networking-bigswitch,wolverineav/networking-bigswitch,wolverineav/networking-bigswitch,openstack/networking-bigswitch,stackforge/networking-bigswitch