Fix NeutronLoadBalancerTest.test_neutron_loadbalancer timeout

NeutronLoadBalancerTest.test_neutron_loadbalancer timeout
happens occasionally. Added WaitCondition resource to
signal back after SimpleHTTPServer is started.

Change-Id: I73085d1b20277fba9f28460abaa991d489d2447a
Closes-Bug: #1437203
diff --git a/scenario/test_neutron_loadbalancer.py b/scenario/test_neutron_loadbalancer.py
index bbe85bc..fafa9be 100644
--- a/scenario/test_neutron_loadbalancer.py
+++ b/scenario/test_neutron_loadbalancer.py
@@ -55,7 +55,8 @@
             'flavor': self.conf.minimal_instance_type,
             'image': self.conf.image_ref,
             'private_subnet_id': self.net['subnets'][0],
-            'external_network_id': self.public_net['id']
+            'external_network_id': self.public_net['id'],
+            'timeout': self.conf.build_timeout
         }
 
         # Launch stack
@@ -70,7 +71,7 @@
         server1_ip = self._stack_output(stack, 'serv1_ip')
         server2_ip = self._stack_output(stack, 'serv2_ip')
 
-        # Check connection and info about received responces
+        # Check connection and info about received responses
         self.check_connectivity(server1_ip)
         self.collect_responses(server1_ip, {'server1\n'})