[Fix] Simplify MISSING_MIMEOLE rule

rules/regexp/headers.lua

@@ -355,12 +355,11 @@ reconf['FAKE_REPLY_C'] = string.format('(%s) & (%s) & (%s) & !(%s)', subj_re, mi
 local has_msmail_pri = 'header_exists(X-MSMail-Priority)'
 local has_mimeole = 'header_exists(X-MimeOLE)'
 local has_squirrelmail_in_mailer = 'X-Mailer=/SquirrelMail\\b/H'
-local has_ips_php_in_mailer = 'X-Mailer=/^IPS PHP Mailer/'
 local has_office12145_in_mailer = 'X-Mailer=/^Microsoft (?:Office )?Outlook 1[245]\\.0/'
-reconf['MISSING_MIMEOLE'] = string.format('(%s) & !(%s) & !(%s) & !(%s) & !(%s) & !(%s) & !(%s)',
-  has_msmail_pri, has_mimeole,
-  has_squirrelmail_in_mailer, xm_mso12,
-  xm_cgpmapi, has_ips_php_in_mailer,
+reconf['MISSING_MIMEOLE'] = string.format('(%s) & !(%s) & !(%s) & !(%s)',
+  has_msmail_pri,
+  has_mimeole,
+  has_squirrelmail_in_mailer,
   has_office12145_in_mailer)
 
 -- Header delimiters