Fixes for diegorusso-aarch64-bigmem (#553)

* no_builds_between: Return a Deferred
* no_builds_between: Get the current date inside the nextBuild function

master/master.cfg

@@ -20,6 +20,7 @@ from functools import partial
 from buildbot.plugins import reporters, schedulers, util
 from buildbot import locks
 from twisted.python import log
+from twisted.internet import defer
 
 import sentry_sdk
 from sentry_sdk.integrations.sqlalchemy import SqlalchemyIntegration
@@ -204,19 +205,20 @@ def get_delay(now, end):
 # Avoid a build to be started between start and end time and delay such build
 # at end time
 def no_builds_between(start, end):
-    now = datetime.now().time()
     start = datetime.strptime(start, "%H:%M").time()
     end = datetime.strptime(end, "%H:%M").time()
     def f(builder, requests):
+        now = datetime.now().time()
         if is_within_time_range(now, start, end):
             delay = get_delay(now, end)
             # Schedule the build later
+            deferred = defer.Deferred()
             builder.master.reactor.callLater(
                 int(delay),
-                builder.buildset_manager.submitBuildSet,
+                deferred.callback,
                 requests[0],
             )
-            return None
+            return deferred
         # Schedule the build now
         return requests[0]
     return f