exim: move to "Mail" menu

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
diff --git a/package/Config.in b/package/Config.in
index 9d8b31f..cc28d51 100644
--- a/package/Config.in
+++ b/package/Config.in
@@ -857,6 +857,7 @@
 endmenu
 
 menu "Mail"
+source "package/exim/Config.in"
 source "package/fetchmail/Config.in"
 source "package/heirloom-mailx/Config.in"
 source "package/libesmtp/Config.in"
@@ -897,7 +898,6 @@
 source "package/dropbear/Config.in"
 source "package/ebtables/Config.in"
 source "package/ethtool/Config.in"
-source "package/exim/Config.in"
 source "package/foomatic-filters/Config.in"
 source "package/fping/Config.in"
 source "package/gesftpserver/Config.in"