Add cgit_query.nohead flag

This flag is set when no HEAD is specified in the querystring. Currently
it has no users, but it will be used by ui-snapshot to invoke a DWIM-mode
where the revision is extracted from the snapshot name.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
diff --git a/cgit.h b/cgit.h
index d07185c..91db98a 100644
--- a/cgit.h
+++ b/cgit.h
@@ -120,6 +120,7 @@
 	char *mimetype;
 	char *url;
 	int   ofs;
+	int nohead;
 };
 
 struct cgit_config {