Fix handling of multi-part branches in the build triggers

Fixes #1360

data/database.py

@@ -665,6 +665,12 @@ class BUILD_PHASE(object):
   WAITING = 'waiting'
   COMPLETE = 'complete'
 
+  @classmethod
+  def is_terminal_phase(cls, phase):
+    return (phase == cls.COMPLETE or
+            phase == cls.ERROR or
+            phase == cls.INTERNAL_ERROR)
+
 
 class QueueItem(BaseModel):
   queue_name = CharField(index=True, max_length=1024)