Have lib/tempest to create shared network

In order to make sure not possible to introduce a change in tempest
which breaks the shared network compatibility.

Depends-On: I6e3e53c4ac26b4fef09fefb9c590dfa91f577565

Change-Id: Ib2e7096175c991acf35de04e840ac188752d3c17

Author: afazekas

lib/tempest

@@ -242,6 +242,9 @@ function configure_tempest {
     # and the public_network_id should not be set.
     if [[ "$NEUTRON_CREATE_INITIAL_NETWORKS" == "True" ]] && is_networking_extension_supported 'external-net'; then
         public_network_id=$(openstack network show -f value -c id $PUBLIC_NETWORK_NAME)
+        # make sure shared network presence does not confuses the tempest tests
+        openstack network create --share shared
+        openstack subnet create --description shared-subnet --subnet-range ${TEMPEST_SHARED_POOL:-192.168.233.0/24} --network shared shared-subnet
     fi
 
     iniset $TEMPEST_CONFIG DEFAULT use_syslog $SYSLOG