Install test_server.bin in well known location

This patch installs and uses test_server.bin from
/opt/octavia-tempest-plugin as a well known location on the
filesystem. This way tests, like grenade, that run the devstack
plugins once in /old paths, can find the binary when running from
/new paths.

Change-Id: Ia78f16fde026269dec01f4dceb202842ad12a557
diff --git a/octavia_tempest_plugin/tests/test_base.py b/octavia_tempest_plugin/tests/test_base.py
index f260e88..669a33c 100644
--- a/octavia_tempest_plugin/tests/test_base.py
+++ b/octavia_tempest_plugin/tests/test_base.py
@@ -13,7 +13,6 @@
 #    under the License.
 
 import ipaddress
-import pkg_resources
 import random
 import shlex
 import string
@@ -849,8 +848,7 @@
 
     @classmethod
     def _install_start_webserver(cls, ip_address, ssh_key, start_id):
-        local_file = pkg_resources.resource_filename(
-            'octavia_tempest_plugin.contrib.test_server', 'test_server.bin')
+        local_file = CONF.load_balancer.test_server_path
         dest_file = '/dev/shm/test_server.bin'
 
         linux_client = remote_client.RemoteClient(