[FIX] Floating IP already exists error

if floating_network_name parameter is set in tempest.conf,
scenario.test_server_basic_ops.verify_ssh test fails
if server already has floating ip set, since it doesn't
check for it's existence. This patch fixes this issue.
More info here [1]

Since get_server_ip() is able to return both fixed and floating ip,
there is no reason to keep the if-else statement anymore.

[1] https://bugs.launchpad.net/tempest/+bug/2020659

Closes-Bug: 2020659
Change-Id: I00a87fe488ebc383c913fa9757f98e19aa2605e9
diff --git a/tempest/scenario/test_server_basic_ops.py b/tempest/scenario/test_server_basic_ops.py
index 5e10ebf..3830fbc 100644
--- a/tempest/scenario/test_server_basic_ops.py
+++ b/tempest/scenario/test_server_basic_ops.py
@@ -49,16 +49,8 @@
 
     def verify_ssh(self, keypair):
         if self.run_ssh:
-            # Obtain a floating IP if floating_ips is enabled
-            if (CONF.network_feature_enabled.floating_ips and
-                CONF.network.floating_network_name):
-                fip = self.create_floating_ip(self.instance)
-                self.ip = self.associate_floating_ip(
-                    fip, self.instance)['floating_ip_address']
-            else:
-                server = self.servers_client.show_server(
-                    self.instance['id'])['server']
-                self.ip = self.get_server_ip(server)
+            # Obtain server IP
+            self.ip = self.get_server_ip(self.instance)
             # Check ssh
             self.ssh_client = self.get_remote_client(
                 ip_address=self.ip,