cleanup(dovecot): remove redundant max_cache_file_size config

fix #644

chatmaild/src/chatmaild/expire.py

@@ -145,6 +145,10 @@ class Expiry:
             changed = True
         if changed:
             self.remove_file(f"{mbox.basedir}/maildirsize")
+        for file in mbox.extrafiles:
+            if "dovecot.index.cache" in file.path.split("/")[-1]:
+                if file.size > 500 * 1024:
+                    self.remove_file(file.path)
 
     def get_summary(self):
         return (

cmdeploy/src/cmdeploy/dovecot/dovecot.conf.j2

@@ -70,12 +70,6 @@ userdb {
 # Mailboxes are stored in the "mail" directory of the vmail user home.
 mail_location = maildir:{{ config.mailboxes_dir }}/%u
 
-# index/cache files are not very useful for chatmail relay operations 
-# but it's not clear how to disable them completely. 
-# According to https://doc.dovecot.org/2.3/settings/advanced/#core_setting-mail_cache_max_size
-# if the cache file becomes larger than the specified size, it is truncated by dovecot 
-mail_cache_max_size = 500K
-
 namespace inbox {
   inbox = yes