cdp: disable failing tests for python3
cdp: disable failing tests for python3

scapy in python3 does not seem to allow creating invalid protocol
packets. Suggest the maintainer rewrite the invalid tests so they
also work for python3. In the mean time they are disabled.

Type: fix
Signed-off-by: Ole Troan <aeed71d78dc09e4764ceac69b111eee9b50cfdd0@cisco.com>
Change-Id: I554d57528422c98c6df4ba76eeae38c03f512a38

vpp-dev/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,vpp-dev/vpp,vpp-dev/vpp,vpp-dev/vpp,vpp-dev/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp,FDio/vpp,vpp-dev/vpp,FDio/vpp,FDio/vpp