Allow whitespaces in domain ACL regex

In some cases there are extraneous spaces in the configuration file for visual aid (or simply accidental) preventing the domains from being picked up. Also adding `req.ssl_sni` as a valid criterion for non-http TLS traffic.

certbot_haproxy/constants.py

@@ -57,8 +57,8 @@ from certbot import errors
 from certbot_haproxy.util import MemoiseNoArgs
 
 RE_HAPROXY_DOMAIN_ACL = re.compile(
-    r'\s*acl (?P<name>[0-9a-z_\-.]+) '
-    r'hdr\(host\) -i '
+    r'\s*acl\s+(?P<name>[0-9a-z_\-.]+)\s+'
+    r'(?:hdr\(host\)|req\.ssl_sni)\s+-i\s+'
     r'(?P<domain>'  # Start group "domain"
     r'(?:[0-9-a-z](?:[a-z0-9-]{0,61}[a-z0-9]\.)+)'  # (sub-)domain parts
     r'(?:[0-9-a-z](?:[a-z0-9-]{0,61}[a-z0-9]))'  # TLD part