lisp: fix unitialized ip prefix in cp unit test
lisp: fix unitialized ip prefix in cp unit test

Type: fix

Found by coverity.

Change-Id: Ibfc753d2c42219d275e3722d6ce1ef0cec189adf
Signed-off-by: Florin Coras <c9715e5cdf0718c2e9b10678757dfb027875eba2@cisco.com>

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