fix the exception of merge same virtualhost using compose v1

Author: tifayuki

haproxy/parser/base_parser.py

@@ -25,7 +25,10 @@ def _merge_services_with_same_vhost(self):
             del self.details[service_alias]
 
             for route in self.routes[service_alias]:
-                self.routes[services_with_same_vhost[service_alias]].append(route)
+                if services_with_same_vhost[service_alias] not in self. routes:
+                    self.routes[services_with_same_vhost[service_alias]] = [route]
+                else:
+                    self.routes[services_with_same_vhost[service_alias]].append(route)
             del self.routes[service_alias]
 
             vhosts = []