Fix maildir name parsing

mailfilter-parse.lisp

      until (or (eq line 'eof) (funcall test-func line))))
 
 (defun convert-maildir-value (value)
-  (remove #\" (cl-ppcre:regex-replace-all "${HOME}" value (user-homedir-pathname))))
+  (pathname (remove #\" (cl-ppcre:regex-replace-all "\\${HOME}" value (princ-to-string (user-homedir-pathname))))))
 
 (defun set-maildir (line hash)
-  (let ((maildir (convert-maildir-value (car (last (split-sequence:split-sequence "=" line))))))
+  (let ((maildir (convert-maildir-value (car (last (split-sequence:split-sequence #\= line))))))
     (setf (gethash "maildir" hash) maildir)
     (setf *maildir* maildir)))