tests: Ignore log setting extended ack support failed.

The test error log 'setting extended ack support failed' in the test
results may cause test failures. However, according to the OVS commit[1],
this is not a critical issue, so we can safely ignore this log.

[1]openvswitch/ovs@812164a

Submitted-at: #234
Signed-off-by: Xie Liu <liushyshy@gmail.com>
Signed-off-by: Dumitru Ceara <dceara@redhat.com>

tests/ofproto-macros.at

@@ -288,6 +288,7 @@ check_logs () {
 /ovs_rcu.*blocked [[0-9]]* ms waiting for .* to quiesce/d
 /Dropped [[0-9]]* log messages/d
 /.*Trying to release unknown interface.*/d
+/setting extended ack support failed/d
 /|WARN|/p
 /|ERR|/p
 /|EMER|/p" ${logs}