[interchange] Log the actual error, as order-desk version does

[Josh Lavin]

commit 645eb9bcd3b482d949c5c8b6230d75ba45e5e80d
Author: Josh Lavin <digory at cpan.org>
Date:   Wed Jul 5 15:17:42 2017 -0700

    Log the actual error, as order-desk version does

 dist/strap/etc/log_transaction |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/dist/strap/etc/log_transaction b/dist/strap/etc/log_transaction
index 764dbea..a594db3 100644
--- a/dist/strap/etc/log_transaction
+++ b/dist/strap/etc/log_transaction
@@ -281,7 +281,7 @@ Set order number in session: [calc]
         [/seti]
         Auto-created user [seti auto_username][data session username][/seti][scratch auto_username].
     [else]
-    Auto-create of user failed.
+    Auto-create of user failed. Reason: [data session failure]
     [perl] die errmsg("Auto-create of user failed."); [/perl]
     [/else]
     [/if]