Also add the message in C.

4d6ec42a · Arnaud Bergeron · d53d21a6 · 4d6ec42a · 4d6ec42a · 4d6ec42a
--- a/theano/scan_module/scan_perform.c
+++ b/theano/scan_module/scan_perform.c
--- a/theano/scan_module/scan_perform.pyx
+++ b/theano/scan_module/scan_perform.pyx
--- a/theano/scan_module/scan_perform_ext.py
+++ b/theano/scan_module/scan_perform_ext.py