Allow the individual build manager types to specify how long the queue should wait before retring a job that fails to schedule.

buildman/manager/enterprise.py

@@ -8,6 +8,7 @@ from buildman.manager.basemanager import BaseManager
 from trollius import From, Return, coroutine
 
 REGISTRATION_REALM = 'registration'
+RETRY_TIMEOUT = 5
 logger = logging.getLogger(__name__)
 
 class DynamicRegistrationComponent(BaseComponent):
@@ -61,13 +62,13 @@ class EnterpriseManager(BaseManager):
   def schedule(self, build_job):
     """ Schedules a build for an Enterprise Registry. """
     if self.shutting_down or not self.ready_components:
-      raise Return(False)
+      raise Return(False, RETRY_TIMEOUT)
 
     component = self.ready_components.pop()
 
     yield From(component.start_build(build_job))
 
-    raise Return(True)
+    raise Return(True, None)
 
   @coroutine
   def build_component_ready(self, build_component):