(elmo-network-session-idle-timeout): Fix customization type mismatch.

diff --git a/elmo/elmo-net.el b/elmo/elmo-net.el
index 02782b3..28d0620 100644 (file)
--- a/elmo/elmo-net.el
+++ b/elmo/elmo-net.el
@@ -61,7 +61,7 @@
 If elapsed time since last access is larger than this value,
 cached session is not reused.
 If nil, network cache is reused."
-  :type 'number
+  :type '(choice number (const nil))
   :group 'elmo)
 
 ;;; Code: