Port in use error caused by gevent threads

If the first launch of a service VM coincides with the
timer for service instance check then there is a possibility
that the same port might be used to launch service VMs.
Added mutual exclusion to ensure that the timer check only
happens after the first launch.

Change-Id: Ieef15683f20e08cd1df221ff17a0c9fed4cf6b89
Closes-Bug: #1463745

src/config/svc-monitor/svc_monitor/config_db.py

@@ -317,6 +317,7 @@ def __init__(self, uuid, obj_dict=None):
         self.virtual_machines = set()
         self.params = None
         self.state = 'init'
+        self.launch_count = 0
         self.image = None
         self.flavor = None
         self.max_instances = 0

src/config/svc-monitor/svc_monitor/svc_monitor.py

@@ -696,6 +696,7 @@ def _create_service_instance(self, si):
                     st.virtualization_type)
         except Exception:
             cgitb_error_log(self)
+        si.launch_count += 1
 
     def _delete_service_instance(self, vm):
         self.logger.log_info("Deleting VM %s %s" %
@@ -766,7 +767,7 @@ def timer_callback(monitor):
     si_id_list = list(ServiceInstanceSM._dict.keys())
     for si_id in si_id_list:
         si = ServiceInstanceSM.get(si_id)
-        if not si:
+        if not si or not si.launch_count:
             continue
         if not monitor._check_service_running(si):
             monitor._relaunch_service_instance(si)