Skip test_connectivity_min_max_mtu if cirros image is used

Command "ping" available in cirros image don't have "-M" option.
This is necessary in test_connectivity_min_max_mtu scenario tests
to check connectivity without fragmenting packets.
So those tests will always fail with cirros and should be skipped
in such case.

Change-Id: Idb63cb37f6e1cc467106ea3ee99727824a4b1529
Closes-Bug: #1786472
1 file changed