Change check for loadbalancer in skip_checks()

Runtest generates service_available section
for load balancer as 'load_balancer'

In other hand at the skip_checks in pike
we use 'loadbalancer' transcription

Change-Id: Id009fd153ea7265c0e48a6bef3ee1a557b63f664
Related-Prod:PROD-25925
diff --git a/octavia_tempest_plugin/config.py b/octavia_tempest_plugin/config.py
index 36cb5ba..0b22b0e 100644
--- a/octavia_tempest_plugin/config.py
+++ b/octavia_tempest_plugin/config.py
@@ -18,7 +18,7 @@
 
 
 service_option = cfg.BoolOpt(
-    'loadbalancer',
+    'load_balancer',
     default=True,
     help="Whether or not loadbalancing service is expected to be available"
 )
diff --git a/octavia_tempest_plugin/tests/v2/base.py b/octavia_tempest_plugin/tests/v2/base.py
index 7fec324..19b5a17 100644
--- a/octavia_tempest_plugin/tests/v2/base.py
+++ b/octavia_tempest_plugin/tests/v2/base.py
@@ -43,11 +43,11 @@
     def skip_checks(cls):
         super(BaseLoadbalancerTest, cls).skip_checks()
 
-        if not CONF.service_available.loadbalancer:
+        if not CONF.service_available.load_balancer:
             raise cls.skipException("Loadbalancing service is not available.")
 
         service_list = {
-            'loadbalancing': CONF.service_available.loadbalancer,
+            'loadbalancing': CONF.service_available.load_balancer,
             'compute': CONF.service_available.nova,
             'image': CONF.service_available.glance,
             'neutron': CONF.service_available.neutron