ignore build directory for pep8
ignore build directory for pep8

this mirrors the excludes from nova.

Change-Id: I0ca5f02918842fc708c704fcf2845936dc1c5965

stackforge/networking-mlnx,openstack/networking-mlnx,stackforge/networking-mlnx,openstack/networking-mlnx,moshele/networking-mlnx-master,moshele/networking-mlnx