Drop some hacks that we needed for Ubuntu 18.04

* certbot's PPA is no longer needed because a recent version is now included in the Ubuntu respository.
* Un-pin b2sdk (reverts 69d8fdef99 and d829d74048).
* Revert boto+s3 workaround for duplicity (partial revert of 99474b348f).
* Revert old "fix boto 2 conflict on Google Compute Engine instances" (cf33be4596) which is probably no longer needed.

management/backup.py

@@ -12,7 +12,7 @@ import dateutil.parser, dateutil.relativedelta, dateutil.tz
 import rtyaml
 from exclusiveprocess import Lock
 
-from utils import load_environment, shell, wait_for_service, fix_boto
+from utils import load_environment, shell, wait_for_service
 
 def backup_status(env):
 	# If backups are dissbled, return no status.
@@ -197,12 +197,7 @@ def get_duplicity_target_url(config):
 		from urllib.parse import urlsplit, urlunsplit
 		target = list(urlsplit(target))
 
-		# Duplicity now defaults to boto3 as the backend for S3, but we have
-		# legacy boto installed (boto3 doesn't support Ubuntu 18.04) so
-		# we retarget for classic boto.
-		target[0] = "boto+" + target[0]
-
-		# In addition, although we store the S3 hostname in the target URL,
+		# Although we store the S3 hostname in the target URL,
 		# duplicity no longer accepts it in the target URL. The hostname in
 		# the target URL must be the bucket name. The hostname is passed
 		# via get_duplicity_additional_args. Move the first part of the
@@ -452,7 +447,6 @@ def list_target_files(config):
 
 	elif target.scheme == "s3":
 		# match to a Region
-		fix_boto() # must call prior to importing boto
 		import boto.s3
 		from boto.exception import BotoServerError
 		custom_region = False

management/daemon.py

@@ -121,7 +121,6 @@ def index():
 	no_users_exist = (len(get_mail_users(env)) == 0)
 	no_admins_exist = (len(get_admins(env)) == 0)
 
-	utils.fix_boto() # must call prior to importing boto
 	import boto.s3
 	backup_s3_hosts = [(r.name, r.endpoint) for r in boto.s3.regions()]
 

management/utils.py

@@ -175,14 +175,6 @@ def wait_for_service(port, public, env, timeout):
 				return False
 		time.sleep(min(timeout/4, 1))
 
-def fix_boto():
-	# Google Compute Engine instances install some Python-2-only boto plugins that
-	# conflict with boto running under Python 3. Disable boto's default configuration
-	# file prior to importing boto so that GCE's plugin is not loaded:
-	import os
-	os.environ["BOTO_CONFIG"] = "/etc/boto3.cfg"
-
-
 if __name__ == "__main__":
 	from web_update import get_web_domains
 	env = load_environment()