multitenancy: Don't use fixed IPs in the test

Currently used fixed IPs didn't work on cloud with HA controllers as one
of IP addresses collided with an address assigned to DHCP port. This
patch removes fixed IPs and lets Neutron to assign IP to booted
instances. Later, those addresses are taken from server response and
reused.

Story: 2004330
Task: 27913

Change-Id: I3335ae43c17298f48cf869553e393df9ba7a070b
diff --git a/ironic_tempest_plugin/tests/scenario/test_baremetal_multitenancy.py b/ironic_tempest_plugin/tests/scenario/test_baremetal_multitenancy.py
index 69ee6c8..f12dc93 100644
--- a/ironic_tempest_plugin/tests/scenario/test_baremetal_multitenancy.py
+++ b/ironic_tempest_plugin/tests/scenario/test_baremetal_multitenancy.py
@@ -91,8 +91,6 @@
     def test_baremetal_multitenancy(self):
 
         tenant_cidr = '10.0.100.0/24'
-        fixed_ip1 = '10.0.100.3'
-        fixed_ip2 = '10.0.100.5'
         keypair = self.create_keypair()
         network, subnet, router = self.create_tenant_network(
             self.os_primary, tenant_cidr)
@@ -103,8 +101,8 @@
             clients=self.os_primary,
             keypair=keypair,
             net_id=network['id'],
-            fixed_ip=fixed_ip1
         )
+        fixed_ip1 = instance1['addresses'][network['name']][0]['addr']
         floating_ip1 = self.create_floating_ip(
             instance1,
         )['floating_ip_address']
@@ -121,8 +119,8 @@
             keypair=alt_keypair,
             clients=self.os_alt,
             net_id=alt_network['id'],
-            fixed_ip=fixed_ip2
         )
+        fixed_ip2 = alt_instance['addresses'][alt_network['name']][0]['addr']
         alt_floating_ip = self.create_floating_ip(
             alt_instance,
             client=self.os_alt.floating_ips_client