celery: drop config settings not supported in Celery 4

CELERY_SEND_TASK_ERROR_EMAILS has been removed, according to
https://docs.celeryproject.org/en/3.0/whatsnew-4.0.html#features-removed-for-simplicity :
"Tasks no longer sends error emails. This also removes support for
app.mail_admins, and any functionality related to sending emails."

The "ADMINS" prefix might be a left-over from the long removed
celery.conf.ADMINS - last seen on
https://docs.celeryproject.org/en/2.1-archived/reference/celery.conf.html#celery.conf.ADMINS .

The "ROUTES" prefix might refer to "CELERY_ROUTES" ... but it doesn't take a
simple string list anyway, so there is no point in treating it as a list value.

development.ini

@@ -257,7 +257,6 b' broker.url = amqp://kallithea:thepasswor'
 
 celery.result.backend = db+sqlite:///celery-results.db
 
-#celery.send.task.error.emails = true
 #celery.amqp.task.result.expires = 18000
 
 celeryd.concurrency = 2

kallithea/lib/celerypylons/__init__.py

@@ -31,7 +31,7 b' def celery_config(config):'
     celery_config = CeleryConfig()
 
     PREFIXES = """ADMINS BROKER CASSANDRA CELERYBEAT CELERYD CELERYMON CELERY EMAIL SERVER""".split()
-    LIST_PARAMS = """CELERY_IMPORTS ADMINS ROUTES CELERY_ACCEPT_CONTENT""".split()
+    LIST_PARAMS = """CELERY_IMPORTS CELERY_ACCEPT_CONTENT""".split()
 
     for config_key, config_value in sorted(config.items()):
         celery_key = config_key.replace('.', '_').upper()

kallithea/lib/paster_commands/template.ini.mako

@@ -363,7 +363,6 b' broker.url = amqp://kallithea:thepasswor'
 
 celery.result.backend = db+sqlite:///celery-results.db
 
-#celery.send.task.error.emails = true
 #celery.amqp.task.result.expires = 18000
 
 celeryd.concurrency = 2