Bump Cirros version used in CI jobs to 0.6.1

It didn't bumps Cirros version used for networking-sfc jobs because it
seems that in Cirros newer than 0.5.1 traceroute output is different and
this is causing failures of the SFC scenario job.

Change-Id: Ibd28503b7e071b9fec067f8c61dd49302e1ab75a
2 files changed