save traceback in case of error creating ticket (#12607)

mail2redmine.py

@@ -7,6 +7,7 @@ import tempfile
 import uuid
 import smtplib
 import subprocess
+import traceback
 
 import redmine
 from redmine import Redmine
@@ -133,5 +134,9 @@ if __name__ == '__main__':
         mail_dump.write(mail)
     try:
         create_ticket(mail)
-    except:
+    except Exception as e:
         exim = subprocess.Popen(['/usr/sbin/exim', FALLBACK_EMAIL], stdin=file(filename))
+        trace = traceback.format_exc()
+        filename = os.path.join(mail_dumps_dir, '%s.trace' % uuid.uuid4())
+        with open(filename, 'w') as mail_dump:
+            mail_dump.write(trace)